Pregnancy is the time during which one or more
offspring
In biology, offspring are the young creation of living organisms, produced either by a single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a more general way. This ca ...
develops (
gestates) inside a
woman's uterus
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
(womb).
A multiple pregnancy
A multiple birth is the culmination of one multiple pregnancy, wherein the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such bir ...
involves more than one offspring, such as with twin
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two em ...
s.
Pregnancy usually occurs by sexual intercourse
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal pene ...
, but can also occur through assisted reproductive technology
Assisted reproductive technology (ART) includes medical procedures used primarily to address infertility. This subject involves procedures such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), cryopreservation of gamet ...
procedures. A pregnancy may end in a live birth, a miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemica ...
, an induced abortion
Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pregnan ...
, or a stillbirth
Stillbirth is typically defined as fetal death at or after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without signs of life. A stillbirth can result in the feeling of guilt or grief in the mother. The term ...
. Childbirth
Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births glob ...
typically occurs around 40 weeks from the start of the last menstrual period
Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of horm ...
(LMP), a span known as the gestational age
In obstetrics, gestational age is a measure of the age of a pregnancy which is taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method if available. Su ...
.[ This is just over nine months. Counting by ]fertilization age
Human fertilization is the union of a human egg and sperm, occurring primarily in the ampulla of the fallopian tube. The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scient ...
, the length is about 38 weeks. Pregnancy is "the presence of an implanted human embryo or fetus in the uterus"; implantation occurs on average 8–9 days after fertilization. An ''embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
'' is the term for the developing offspring during the first seven weeks following implantation (i.e. ten weeks' gestational age), after which the term ''fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...
'' is used until birth.
Signs and symptoms of early pregnancy may include missed periods, tender breasts, morning sickness
Morning sickness, also called nausea and vomiting of pregnancy (NVP), is a symptom of pregnancy that involves nausea or vomiting. Despite the name, nausea or vomiting can occur at any time during the day. Typically the symptoms occur between th ...
(nausea and vomiting), hunger, implantation bleeding
Implantation (nidation) is the stage in the embryonic development of mammals in which the blastocyst hatches as the embryo, adheres, and invades into the wall of the female's uterus. Implantation is the first stage of gestation, and when suc ...
, and frequent urination. Pregnancy may be confirmed with a pregnancy test
A pregnancy test is used to determine whether a female is pregnant or not. The two primary methods are testing for the female pregnancy hormone (human chorionic gonadotropin (hCG)) in blood or urine using a pregnancy test kit, and scanning with ...
. Methods of birth control
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr ...
—or, more accurately, ''contraception''—are used to avoid pregnancy.
Pregnancy is divided into three trimesters of approximately three months each. The first trimester
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ...
includes conception, which is when the sperm fertilizes the egg. The fertilized egg
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism.
In multicellula ...
then travels down the Fallopian tube
The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In o ...
and attaches to the inside of the uterus
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
, where it begins to form the embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
and placenta
The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mate ...
. During the first trimester, the possibility of miscarriage (natural death of embryo or fetus) is at its highest. Around the middle of the second trimester, movement of the fetus may be felt. At 28 weeks, more than 90% of babies can survive outside of the uterus if provided with high-quality medical care, though babies born at this time will likely experience serious health complications such as heart and respiratory problems and long-term intellectual and developmental disabilities.
Prenatal care
Prenatal care, also known as antenatal care, is a type of preventive healthcare. It is provided in the form of medical checkups, consisting of recommendations on managing a healthy lifestyle and the provision of medical information such as materna ...
improves pregnancy outcomes.[ ]Nutrition
Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficient ...
during pregnancy is important to ensure healthy growth of the fetus. Prenatal care may also include avoiding drugs
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhalati ...
, tobacco smoking
Tobacco smoking is the practice of burning tobacco and ingesting the resulting smoke. The smoke may be inhaled, as is done with cigarettes, or simply released from the mouth, as is generally done with pipes and cigars. The practice is beli ...
, and alcohol, taking regular exercise, having blood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a choles ...
s, and regular physical examination
In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the pati ...
s. Complications of pregnancy
Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal ...
may include disorders of high blood pressure, gestational diabetes
Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and ...
, iron-deficiency anemia
Iron-deficiency anemia is anemia caused by a lack of iron. Anemia is defined as a decrease in the number of red blood cells or the amount of hemoglobin in the blood. When onset is slow, symptoms are often vague such as feeling tired, weak, shor ...
, and severe nausea and vomiting. In the ideal childbirth labor begins on its own when a woman is "at term". Babies born before 37 weeks are " preterm" and at higher risk of health problems such as cerebral palsy
Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, stiff muscles, weak muscles, and tremors. There may be problems with sens ...
.[ Babies born between weeks 37 and 39 are considered "early term" while those born between weeks 39 and 41 are considered "full term".][ Babies born between weeks 41 and 42 weeks are considered "late term" while after 42 weeks they are considered " post term".][ Delivery before 39 weeks by ]labor induction
Labor induction is the process or treatment that stimulates childbirth and delivery. Inducing (starting) labor can be accomplished with pharmaceutical or non-pharmaceutical methods. In Western countries, it is estimated that one-quarter of pregna ...
or caesarean section
Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or m ...
is not recommended unless required for other medical reasons.
About 213 million pregnancies occurred in 2012, of which, 190 million (89%) were in the developing world
A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreeme ...
and 23 million (11%) were in the developed world.[ The number of pregnancies in women aged between 15 and 44 is 133 per 1,000 women.] About 10% to 15% of recognized pregnancies end in miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemica ...
. In 2016, complications of pregnancy resulted in 230,600 maternal deaths
Maternal death or maternal mortality is defined in slightly different ways by several different health organizations. The World Health Organization (WHO) defines maternal death as the death of a pregnant mother due to complications related to pre ...
, down from 377,000 deaths in 1990. Common causes include bleeding
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
, infections
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...
, hypertensive diseases of pregnancy
Hypertensive disease of pregnancy, also known as maternal hypertensive disorder, is a group of high blood pressure disorders that include preeclampsia, preeclampsia superimposed on chronic hypertension, gestational hypertension, and chronic hyperte ...
, obstructed labor
Obstructed labour, also known as labour dystocia, is the baby not exiting the pelvis because it is physically block during childbirth although the uterus contracts normally. Complications for the baby include not getting enough oxygen which ma ...
, miscarriage, abortion, or ectopic pregnancy
Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptom ...
.[ Globally, 44% of pregnancies are ]unplanned
''Unplanned'' is a 2019 American drama film written and directed by Cary Solomon and Chuck Konzelman. It is based on the disputed 2011 memoir ''Unplanned'' by anti-abortion activist Abby Johnson. The film stars Ashley Bratcher as Johnson, foll ...
.[ Over half (56%) of unplanned pregnancies are aborted.] Among unintended pregnancies in the United States, 60% of the women used birth control
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr ...
to some extent during the month pregnancy began.
Terminology
Associated terms for pregnancy are ''gravid'' and ''parous''. ''Gravidus'' and ''gravid'' come from the Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
word meaning "heavy" and a pregnant female is sometimes referred to as a ''gravida''. ''Gravidity
In biology and human medicine, gravidity and parity are the number of times a woman is or has been pregnant (gravidity) and carried the pregnancies to a viable gestational age (parity). These terms are usually coupled, sometimes with additional t ...
'' refers to the number of times that a female has been pregnant. Similarly, the term ''parity
Parity may refer to:
* Parity (computing)
** Parity bit in computing, sets the parity of data for the purpose of error detection
** Parity flag in computing, indicates if the number of set bits is odd or even in the binary representation of the ...
'' is used for the number of times that a female carries a pregnancy to a viable stage. Twins
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two em ...
and other multiple births are counted as one pregnancy and birth.
A woman who has never been pregnant is referred to as a ''nulligravida.'' A woman who is (or has been only) pregnant for the first time is referred to as a ''primigravida'',[, page 596.] and a woman in subsequent pregnancies as a ''multigravida
In biology and human medicine, gravidity and parity are the number of times a woman is or has been pregnant (gravidity) and carried the pregnancies to a viable gestational age (parity). These terms are usually coupled, sometimes with additional te ...
'' or as ''multiparous.'' Therefore, during a second pregnancy a woman would be described as ''gravida 2, para 1'' and upon live delivery as ''gravida 2, para 2.'' In-progress pregnancies, abortion
Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pre ...
s, miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemica ...
s and/or stillbirth
Stillbirth is typically defined as fetal death at or after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without signs of life. A stillbirth can result in the feeling of guilt or grief in the mother. The term ...
s account for parity values being less than the gravida number. Women who have never carried a pregnancy more than 20 weeks are referred to as ''nulliparous''.
A pregnancy is considered ''term'' at 37 weeks of gestation. It is ''preterm'' if less than 37 weeks and ''postterm'' at or beyond 42 weeks of gestation. American College of Obstetricians and Gynecologists have recommended further division with ''early term'' 37 weeks up to 39 weeks, ''full term'' 39 weeks up to 41 weeks, and ''late term'' 41 weeks up to 42 weeks. The terms ''preterm'' and ''postterm'' have largely replaced earlier terms of ''premature'' and ''postmature''. ''Preterm'' and ''postterm'' are defined above, whereas ''premature'' and ''postmature'' have historical meaning and relate more to the infant's size and state of development rather than to the stage of pregnancy.
Signs and symptoms
![Melasmablemish](https://upload.wikimedia.org/wikipedia/commons/2/27/Melasmablemish.jpg)
The usual signs and symptoms of pregnancy
Signs and symptoms of pregnancy are common, benign conditions that result from the changes to the body that occur during pregnancy. Signs and symptoms of pregnancy typically change as pregnancy progresses, although several symptoms may be present ...
do not significantly interfere with activities of daily living
Activity may refer to:
* Action (philosophy), in general
* Human activity: human behavior, in sociology behavior may refer to all basic human actions, economics may study human economic activities and along with cybernetics and psychology may s ...
or pose a health-threat to the mother or baby. However, pregnancy complications
Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal ...
can cause other more severe symptoms, such as those associated with anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...
.
Common signs and symptoms of pregnancy include:
* Tiredness
Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
* Morning sickness
Morning sickness, also called nausea and vomiting of pregnancy (NVP), is a symptom of pregnancy that involves nausea or vomiting. Despite the name, nausea or vomiting can occur at any time during the day. Typically the symptoms occur between th ...
* Constipation
Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel moveme ...
* Pelvic girdle pain
Pelvic girdle pain (abbreviated PGP) can be described as a pregnancy discomfort for some women and a severe disability for others. PGP can cause pain, instability and limitation of mobility and functioning in any of the three pelvic joints. PGP ha ...
* Back pain
Back pain is pain felt in the back. It may be classified as neck pain (cervical), middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. The lumbar area is the most common ...
* Braxton Hicks contractions
Braxton Hicks contractions, also known as practice contractions or false labor, are sporadic uterine contractions that may start around six weeks into a pregnancy. However, they are usually felt in the second or third trimester of pregnancy.
...
. Occasional, irregular, and often painless contractions that occur several times per day.
* Peripheral edema
Peripheral edema is edema (accumulation of fluid causing swelling) in tissues perfused by the peripheral vascular system, usually in the lower limbs. In the most dependent parts of the body (those hanging distally), it may be called dependent ede ...
swelling of the lower limbs. Common complaint in advancing pregnancy. Can be caused by inferior vena cava syndrome
Inferior vena cava syndrome (IVCS) is a very rare constellation of symptoms resulting from either an obstruction, or stenosis of the inferior vena cava. It can be caused by physical invasion or compression by a pathological process or by thrombosi ...
resulting from compression of the inferior vena cava
The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of th ...
and pelvic veins by the uterus
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
leading to increased hydrostatic pressure
Fluid statics or hydrostatics is the branch of fluid mechanics that studies the condition of the equilibrium of a floating body and submerged body " fluids at hydrostatic equilibrium and the pressure in a fluid, or exerted by a fluid, on an i ...
in lower extremities.
* Low blood pressure
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the di ...
often caused by compression of both the inferior vena cava and the abdominal aorta
In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax).
Structure
The abdominal aorta begins at the level of the diaphr ...
( aortocaval compression syndrome).
* Increased urinary frequency
Polyuria () is excessive or an abnormally large production or passage of urine (greater than 2.5 L or 3 L over 24 hours in adults). Increased production and passage of urine may also be termed diuresis. Polyuria often appears in conjunction wit ...
. A common complaint, caused by increased intravascular volume, elevated glomerular filtration rate
Renal functions include maintaining an acid–base balance; regulating fluid balance; regulating sodium, potassium, and other electrolytes; clearing toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pre ...
, and compression of the bladder
The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine en ...
by the expanding uterus.
* Urinary tract infection
A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...
* Varicose veins
Varicose veins, also known as varicoses, are a medical condition in which superficial veins become enlarged and twisted. These veins typically develop in the legs, just under the skin. Varicose veins usually cause few symptoms. However, some indiv ...
. Common complaint caused by relaxation of the venous smooth muscle
Smooth muscle is an involuntary non- striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit ...
and increased intravascular pressure.
* Hemorrhoids
Hemorrhoids (or haemorrhoids), also known as piles, are vascular structures in the anal canal. In their normal state, they are cushions that help with stool control. They become a disease when swollen or inflamed; the unqualified term ''h ...
(piles). Swollen veins at or inside the anal area. Caused by impaired venous return, straining associated with constipation, or increased intra-abdominal pressure in later pregnancy.
* Regurgitation, heartburn
Heartburn, also known as pyrosis, cardialgia or acid indigestion, is a burning sensation in the central chest or upper central abdomen. Heartburn is usually due to regurgitation of gastric acid (gastric reflux) into the esophagus. It is the ...
, and nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...
.
* Stretch marks
Stretch marks, also known as striae () or striae distensae, are a form of scarring on the skin with an off-color hue. Over time they may diminish, but will not disappear completely. Striae are caused by tearing of the dermis during periods of r ...
* Breast tenderness
Breast pain is the symptom of discomfort in either one or both breasts. Pain in both breasts is often described as ''breast tenderness'', is usually associated with the menstrual period and is not serious. Pain that involves only one part of a br ...
is common during the first trimester, and is more common in women who are pregnant at a young age.
* Melasma
Melasma (also known as chloasma faciei,James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. . or the mask of pregnancy when present in pregnant women) is a tan or dark ...
, also known as the mask of pregnancy, is a discoloration, most often of the face. It usually begins to fade several months after giving birth.
Timeline
The chronology
Chronology (from Latin ''chronologia'', from Ancient Greek , ''chrónos'', "time"; and , ''-logia'') is the science of arranging events in their order of occurrence in time. Consider, for example, the use of a timeline or sequence of even ...
of pregnancy is, unless otherwise specified, generally given as gestational age
In obstetrics, gestational age is a measure of the age of a pregnancy which is taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method if available. Su ...
, where the starting point is the beginning of the woman's last menstrual period
Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of horm ...
(LMP), or the corresponding age of the gestation as estimated by a more accurate method if available. This model means that the woman is counted as being "pregnant" two weeks before conception and three weeks before implantation. Sometimes, timing may also use the fertilization age
Human fertilization is the union of a human egg and sperm, occurring primarily in the ampulla of the fallopian tube. The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scient ...
, which is the age of the embryo since conception.
Start of gestational age
The American Congress of Obstetricians and Gynecologists
The American College of Obstetricians and Gynecologists (ACOG) is a professional association of physicians specializing in obstetrics and gynecology in the United States. Several Latin American countries are also represented within Districts of ...
recommend the following methods to calculate gestational age:[Obstetric Data Definitions Issues and Rationale for Change – Gestational Age & Term]
from Patient Safety and Quality Improvement at American Congress of Obstetricians and Gynecologists
The American College of Obstetricians and Gynecologists (ACOG) is a professional association of physicians specializing in obstetrics and gynecology in the United States. Several Latin American countries are also represented within Districts of ...
. Created November 2012.
* Directly calculating the days since the beginning of the last menstrual period
Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of horm ...
.
* Early obstetric ultrasound, comparing the size of an embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
or fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...
to that of a reference group of pregnancies of known gestational age (such as calculated from last menstrual periods), and using the mean gestational age of other embryos or fetuses of the same size. If the gestational age as calculated from an early ultrasound is contradictory to the one calculated directly from the last menstrual period, it is still the one from the early ultrasound that is used for the rest of the pregnancy.[
* In case of in vitro fertilization, calculating days since oocyte retrieval or ]co-incubation
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) ...
and adding 14 days.
Trimesters
Pregnancy is divided into three trimesters, each lasting for approximately three months.[ The exact length of each trimester can vary between sources.
*The first trimester begins with the start of gestational age as described above, that is, the beginning of week 1, or 0 weeks + 0 days of gestational age (GA). It ends at week 12 (11 weeks + 6 days of GA)][ or end of week 14 (13 weeks + 6 days of GA).]
*The second trimester is defined as starting, between the beginning of week 13 (12 weeks +0 days of GA)[ and beginning of week 15 (14 weeks + 0 days of GA).][ It ends at the end of week 27 (26 weeks + 6 days of GA)][ or end of week 28 (27 weeks + 6 days of GA).][
*The third trimester is defined as starting, between the beginning of week 28 (27 weeks + 0 days of GA)][ or beginning of week 29 (28 weeks + 0 days of GA).][ It lasts until ]childbirth
Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births glob ...
.
Estimation of due date
Due date estimation basically follows two steps:
* Determination of which time point is to be used as origin
Origin(s) or The Origin may refer to:
Arts, entertainment, and media
Comics and manga
* Origin (comics), ''Origin'' (comics), a Wolverine comic book mini-series published by Marvel Comics in 2002
* The Origin (Buffy comic), ''The Origin'' (Bu ...
for gestational age
In obstetrics, gestational age is a measure of the age of a pregnancy which is taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method if available. Su ...
, as described in the section above.
* Adding the estimated gestational age at childbirth to the above time point. Childbirth on average occurs at a gestational age of 280 days (40 weeks), which is therefore often used as a standard estimation for individual pregnancies. However, alternative durations as well as more individualized methods have also been suggested.
The American College of Obstetricians and Gynecologists
The American College of Obstetricians and Gynecologists (ACOG) is a professional association of physicians specializing in obstetrics and gynecology in the United States. Several Latin American countries are also represented within Districts of ...
divides full term into three devisions:
*Early-term: 37 weeks and 0 days through 38 weeks and 6 days
*Full-term: 39 weeks and 0 days through 40 weeks and 6 days
*Late-term: 41 weeks and 0 days through 41 weeks and 6 days
*Post-term: greater than or equal to 42 weeks and 0 days
''Naegele's rule'' is a standard way of calculating the due date for a pregnancy when assuming a gestational age of 280 days at childbirth. The rule estimates the expected date of delivery (EDD) by adding a year, subtracting three months, and adding seven days to the origin of gestational age. Alternatively there are mobile app
A mobile application or app is a computer program or software application designed to run on a mobile device such as a phone, tablet, or watch. Mobile applications often stand in contrast to desktop applications which are designed to run on d ...
s, which essentially always give consistent estimations compared to each other and correct for leap year
A leap year (also known as an intercalary year or bissextile year) is a calendar year that contains an additional day (or, in the case of a lunisolar calendar, a month) added to keep the calendar year synchronized with the astronomical year or ...
, while pregnancy wheels made of paper can differ from each other by 7 days and generally do not correct for leap year.
Furthermore, actual childbirth has only a certain probability of occurring within the limits of the estimated due date. A study of singleton live births came to the result that childbirth has a standard deviation
In statistics, the standard deviation is a measure of the amount of variation or dispersion of a set of values. A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, whil ...
of 14 days when gestational age is estimated by first trimester ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
, and 16 days when estimated directly by last menstrual period.[
]
Physiology
Capacity
Fertility
Fertility is the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Ferti ...
and fecundity
Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the natural capability to pr ...
are the respective capacities to fertilize
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Pro ...
and establish a clinical pregnancy and have a live birth. Infertility
Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal st ...
is an impaired ability to establish a clinical pregnancy and sterility is the permanent inability to establish a clinical pregnancy.
The capacity for pregnancy depends on the reproductive system
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are ...
, its development and its variation, as well as on the condition of a person.
Women
A woman is an adult female human. Prior to adulthood, a female human is referred to as a girl (a female child or Adolescence, adolescent). The plural ''women'' is sometimes used in certain phrases such as "women's rights" to denote female hum ...
as well as intersex
Intersex people are individuals born with any of several sex characteristics including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical b ...
and transgender
A transgender (often abbreviated as trans) person is someone whose gender identity or gender expression does not correspond with their sex assigned at birth. Many transgender people experience dysphoria, which they seek to alleviate through ...
people who have a functioning female reproductive system
The female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. In humans, the female reproductive system is immature at birth and develops to maturity at puberty to be ...
are capable of pregnancy. In some cases, someone might be able to produce fertilizable eggs, but might not have a womb or none that can sufficiently gestate, in which case they might find surrogacy
Surrogacy is an arrangement, often supported by a legal agreement, whereby a woman agrees to delivery/labour for another person or people, who will become the child's parent(s) after birth. People may seek a surrogacy arrangement when pregna ...
.
Initiation
Through an interplay of hormones that includes follicle stimulating hormone
Follicle-stimulating hormone (FSH) is a gonadotropin, a glycoprotein polypeptide hormone. FSH is synthesized and secreted by the gonadotropic cells of the anterior pituitary gland and regulates the development, growth, pubertal maturation, a ...
that stimulates folliculogenesis
:''Although the process is similar in many animals, this article will deal exclusively with human folliculogenesis.''
In biology, folliculogenesis is the maturation of the ovarian follicle, a densely packed shell of somatic cells that contains a ...
and oogenesis
Oogenesis, ovogenesis, or oögenesis is the differentiation of the ovum (egg cell) into a cell competent to further develop when fertilized. It is developed from the primary oocyte by maturation. Oogenesis is initiated in the embryonic stage.
...
creates a mature egg cell
The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete i ...
, the female gamete
A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...
. Fertilization
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Pro ...
is the event where the egg cell fuses with the male gamete, spermatozoon
A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosom ...
. After the point of fertilization, the fused product of the female and male gamete is referred to as a zygote
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism.
In multicell ...
or fertilized egg. The fusion of female and male gametes usually occurs following the act of sexual intercourse
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal pene ...
. Pregnancy rates for sexual intercourse are highest during the menstrual cycle
The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The ovarian cycle controls the production and release of eggs ...
time from some 5 days before until 1 to 2 days after ovulation. Fertilization can also occur by assisted reproductive technology
Assisted reproductive technology (ART) includes medical procedures used primarily to address infertility. This subject involves procedures such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), cryopreservation of gamet ...
such as artificial insemination
Artificial insemination is the deliberate introduction of sperm into a female's cervix or uterine cavity for the purpose of achieving a pregnancy through in vivo fertilization by means other than sexual intercourse. It is a fertility treatment ...
and in vitro fertilisation
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) ...
.
Fertilization (conception) is sometimes used as the initiation of pregnancy, with the derived age being termed fertilization age
Human fertilization is the union of a human egg and sperm, occurring primarily in the ampulla of the fallopian tube. The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scient ...
. Fertilization usually occurs about two weeks before the ''next'' expected menstrual period.
A third point in time is also considered by some people to be the true beginning of a pregnancy: This is time of implantation, when the future fetus attaches to the lining of the uterus. This is about a week to ten days after fertilization.
Development of embryo and fetus
The sperm and the egg cell, which has been released from one of the female's two ovaries
The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...
, unite in one of the two Fallopian tube
The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In o ...
s. The fertilized egg, known as a zygote
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism.
In multicell ...
, then moves toward the uterus, a journey that can take up to a week to complete. Cell division begins approximately 24 to 36 hours after the female and male cells unite. Cell division continues at a rapid rate and the cells then develop into what is known as a blastocyst
The blastocyst is a structure formed in the early embryonic development of mammals. It possesses an inner cell mass (ICM) also known as the ''embryoblast'' which subsequently forms the embryo, and an outer layer of trophoblast cells called th ...
. The blastocyst arrives at the uterus and attaches to the uterine wall, a process known as implantation.
The development of the mass of cells that will become the infant is called embryogenesis
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
during the first approximately ten weeks of gestation. During this time, cells begin to differentiate into the various body systems. The basic outlines of the organ, body, and nervous systems are established. By the end of the embryonic stage, the beginnings of features such as fingers, eyes, mouth, and ears become visible. Also during this time, there is development of structures important to the support of the embryo, including the placenta
The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mate ...
and umbilical cord
In placental mammals, the umbilical cord (also called the navel string, birth cord or ''funiculus umbilicalis'') is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologi ...
. The placenta connects the developing embryo to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. The umbilical cord is the connecting cord from the embryo or fetus to the placenta.
After about ten weeks of gestational age—which is the same as eight weeks after conception—the embryo becomes known as a fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...
. At the beginning of the fetal stage, the risk of miscarriage decreases sharply.[
* Lennart Nilsson, A Child is Born 91 (1990): at eight weeks, "the danger of a miscarriage ... diminishes sharply."
*]
Women's Health Information
", Hearthstone Communications Limited: "The risk of miscarriage decreases dramatically after the 8th week as the weeks go by." Retrieved 2007-04-22. At this stage, a fetus is about in length, the heartbeat is seen via ultrasound, and the fetus makes involuntary motions. During continued fetal development, the early body systems, and structures that were established in the embryonic stage continue to develop. Sex organs begin to appear during the third month of gestation. The fetus continues to grow in both weight and length, although the majority of the physical growth occurs in the last weeks of pregnancy.
Electrical brain activity
Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocor ...
is first detected at the end of week 5 of gestation, but as in brain-dead
Brain death is the permanent, irreversible, and complete loss of brain function which may include cessation of involuntary activity necessary to sustain life. It differs from persistent vegetative state, in which the person is alive and some au ...
patients, it is primitive neural activity rather than the beginning of conscious brain activity. Synapses do not begin to form until week 17. Neural connections between the sensory cortex The sensory cortex can refer informally to the primary somatosensory cortex, or it can be used as a term for the primary and secondary cortices of the different senses (two cortices each, on left and right hemisphere): the visual cortex on the occ ...
and thalamus
The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all direct ...
develop as early as 24 weeks' gestational age, but the first evidence of their function does not occur until around 30 weeks, when minimal consciousness
Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
, dream
A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. Humans spend about two hours dreaming per night, and each dream lasts around 5 to 20 minutes, althou ...
ing, and the ability to feel pain emerges.
Although the fetus begins to move during the first trimester, it is not until the second trimester that movement, known as quickening
In pregnancy terms, quickening is the moment in pregnancy when the pregnant woman starts to feel the fetus' movement in the uterus.
Medical facts
The first natural sensation of quickening may feel like a light tapping or fluttering. These sensat ...
, can be felt. This typically happens in the fourth month, more specifically in the 20th to 21st week, or by the 19th week if the woman has been pregnant before. It is common for some women not to feel the fetus move until much later. During the second trimester, when the body size changes, maternity clothes may be worn.
File:6 weeks pregnant.png, Embryo at 4 weeks after fertilization (gestational age of 6 weeks)
File:10 weeks pregnant.png, Fetus at 8 weeks after fertilization (gestational age of 10 weeks)
File:20 weeks pregnant.png, Fetus at 18 weeks after fertilization (gestational age of 20 weeks)
File:40 weeks pregnant.png, Fetus at 38 weeks after fertilization (gestational age of 40 weeks)
File:Month 1.svg, Relative size in 1st month (simplified illustration)
File:Month 3.svg, Relative size in 3rd month (simplified illustration)
File:Month 5.svg, Relative size in 5th month (simplified illustration)
File:Month 9.svg, Relative size in 9th month (simplified illustration)
Maternal changes
During pregnancy, a woman undergoes many physiological
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemica ...
changes, which are entirely normal, including behavioral
Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as we ...
, cardiovascular
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
, hematologic, metabolic
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
, renal
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; bloo ...
, and respiratory
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies gre ...
changes. Increases in blood sugar
Glycaemia, also known as blood sugar level, blood sugar concentration, or blood glucose level is the measure of glucose concentrated in the blood of humans or other animals. Approximately 4 grams of glucose, a simple sugar, is present in the b ...
, breathing
Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen.
All aerobic creatures need oxygen for cellu ...
, and cardiac output
In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols Q, \dot Q, or \dot Q_ , edited by Catherine E. Williamson, Phillip Bennett is the volumetric flow rate of the heart's pumping output: th ...
are all required. Levels of progesterone
Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the majo ...
and estrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...
s rise continually throughout pregnancy, suppressing the hypothalamic axis and therefore also the menstrual cycle
The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The ovarian cycle controls the production and release of eggs ...
. A full-term pregnancy at an early age (< 25) reduces the risk of breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues.
In females, it serves as the mammary gland, which produces and sec ...
, ovarian and endometrial cancer
Endometrial cancer is a cancer that arises from the endometrium (the lining of the uterus or womb). It is the result of the abnormal growth of cells that have the ability to invade or spread to other parts of the body. The first sign is most ...
and the risk declines further with each additional full-term pregnancy.
The fetus is genetically
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working i ...
different from its mother, and can be viewed as an unusually successful allograft
Allotransplant (''allo-'' meaning "other" in Greek) is the transplantation of cells, tissues, or organs to a recipient from a genetically non-identical donor of the same species. The transplant is called an allograft, allogeneic transplant, o ...
. The main reason for this success is increased immune tolerance
Immune tolerance, or immunological tolerance, or immunotolerance, is a state of unresponsiveness of the immune system to substances or tissue that would otherwise have the capacity to elicit an immune response in a given organism. It is induced by ...
during pregnancy. Immune tolerance is the concept that the body is able to not mount an immune system response against certain triggers.
During the first trimester, minute ventilation
Minute ventilation (or respiratory minute volume or minute volume) is the volume of gas inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a person's lungs per minute. It is an important parameter in respiratory medicine d ...
increases by 40%. The womb will grow to the size of a lemon by eight weeks. Many symptoms and discomforts of pregnancy
Signs and symptoms of pregnancy are common, benign conditions that result from the changes to the body that occur during pregnancy. Signs and symptoms of pregnancy typically change as pregnancy progresses, although several symptoms may be present ...
like nausea and tender breasts appear in the first trimester.
During the second trimester, most women feel more energized, and begin to put on weight as the symptoms of morning sickness subside and eventually fade away. The uterus, the muscular organ that holds the developing fetus, can expand up to 20 times its normal size during pregnancy.
Braxton Hicks contractions
Braxton Hicks contractions, also known as practice contractions or false labor, are sporadic uterine contractions that may start around six weeks into a pregnancy. However, they are usually felt in the second or third trimester of pregnancy.
...
are sporadic uterine contractions that may start around six weeks into a pregnancy; however, they are usually not felt until the second or third trimester.
Final weight gain takes place during the third trimester, which is the most weight gain throughout the pregnancy. The woman's abdomen will transform in shape as it drops due to the fetus turning in a downward position ready for birth. During the second trimester, the woman's abdomen would have been upright, whereas in the third trimester it will drop down low. The fetus moves regularly, and is felt by the woman. Fetal movement can become strong and be disruptive to the woman. The woman's navel
The navel (clinically known as the umbilicus, commonly known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. All placental mammals have a navel, altho ...
will sometimes become convex, "popping" out, due to the expanding abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
.
Head engagement
A cephalic presentation or head presentation or head-first presentation is a situation at childbirth where the fetus is in a longitudinal lie and the head enters the pelvis first; the most common form of cephalic presentation is the vertex pre ...
, also called "lightening" or "dropping", occurs as the fetal head descends into a cephalic presentation
A cephalic presentation or head presentation or head-first presentation is a situation at childbirth where the fetus is in a longitudinal lie and the head enters the pelvis first; the most common form of cephalic presentation is the vertex p ...
. While it relieves pressure on the upper abdomen and gives a renewed ease in breathing, it also severely reduces bladder capacity resulting in a need to void more frequently, and increases pressure on the pelvic floor and the rectum. It is not possible to predict when lightening occurs. In a first pregnancy it may happen a few weeks before the due date, though it may happen later or even not until labor begins, as is typical with subsequent pregnancies.
It is also during the third trimester that maternal activity and sleep positions may affect fetal development due to restricted blood flow. For instance, the enlarged uterus may impede blood flow by compressing the vena cava
In anatomy, the venae cavae (; singular: vena cava ; ) are two large veins (great vessels) that return deoxygenated blood from the body into the heart. In humans they are the superior vena cava and the inferior vena cava, and both empty into th ...
when lying flat, which is relieved by lying on the left side.
Childbirth
Childbirth, referred to as labor and delivery in the medical field, is the process whereby an infant is born.
A woman is considered to be in labour when she begins experiencing regular uterine contractions, accompanied by changes of her cervix—primarily effacement and dilation. While childbirth is widely experienced as painful, some women do report painless labours, while others find that concentrating on the birth helps to quicken labour and lessen the sensations. Most births are successful vaginal births, but sometimes complications arise and a woman may undergo a cesarean section
Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or ...
.
During the time immediately after birth, both the mother and the baby are hormonally cued to bond, the mother through the release of oxytocin
Oxytocin (Oxt or OT) is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. It plays a role in social bonding, reproduction, childbirth, and the period after childbirth. Oxytoc ...
, a hormone also released during breastfeeding
Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that bre ...
. Studies show that skin-to-skin contact between a mother and her newborn immediately after birth is beneficial for both the mother and baby. A review done by the World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...
found that skin-to-skin contact between mothers and babies after birth reduces crying, improves mother–infant interaction, and helps mothers to breastfeed successfully. They recommend that neonates
An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...
be allowed to bond with the mother during their first two hours after birth, the period that they tend to be more alert than in the following hours of early life.
Childbirth maturity stages
In the ideal childbirth
Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births glob ...
labor begins on its own when a woman is "at term".
Events before completion of 37 weeks are considered preterm. Preterm birth
Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is betwee ...
is associated with a range of complications and should be avoided if possible.
Sometimes if a woman's water breaks or she has contractions before 39 weeks, birth is unavoidable. However, spontaneous birth after 37 weeks is considered term and is not associated with the same risks of a preterm birth. Planned birth before 39 weeks by caesarean section
Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or m ...
or labor induction
Labor induction is the process or treatment that stimulates childbirth and delivery. Inducing (starting) labor can be accomplished with pharmaceutical or non-pharmaceutical methods. In Western countries, it is estimated that one-quarter of pregna ...
, although "at term", results in an increased risk of complications.[, which cites
* ] This is from factors including underdeveloped lungs of newborns, infection due to underdeveloped immune system, feeding problems due to underdeveloped brain, and jaundice
Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme meta ...
from underdeveloped liver.
Babies born between 39 and 41 weeks' gestation have better outcomes than babies born either before or after this range. This special time period is called "full term". Whenever possible, waiting for labor to begin on its own in this time period is best for the health of the mother and baby. The decision to perform an induction must be made after weighing the risks and benefits, but is safer after 39 weeks.
Events after 42 weeks are considered postterm. When a pregnancy exceeds 42 weeks, the risk of complications for both the woman and the fetus increases significantly. Therefore, in an otherwise uncomplicated pregnancy, obstetricians usually prefer to induce labour at some stage between 41 and 42 weeks.
Postnatal period
The postpartum period
The postpartum (or postnatal) period begins after childbirth and is typically considered to end within 6 weeks as the mother's body, including hormone levels and uterus size, returns to a non-pregnant state. The terms puerperium, puerperal peri ...
also referred to as the ''puerperium'', is the postnatal period that begins immediately after delivery and extends for about six weeks. During this period, the mother's body begins the return to pre-pregnancy conditions that includes changes in hormone levels and uterus size.
Diagnosis
The beginning of pregnancy may be detected either based on symptoms by the woman herself, or by using pregnancy test
A pregnancy test is used to determine whether a female is pregnant or not. The two primary methods are testing for the female pregnancy hormone (human chorionic gonadotropin (hCG)) in blood or urine using a pregnancy test kit, and scanning with ...
s. However, an important condition with serious health implications that is quite common is the denial of pregnancy by the pregnant woman. About 1 in 475 denials will last until around the 20th week of pregnancy. The proportion of cases of denial, persisting until delivery is about 1 in 2500. Conversely, some non-pregnant women have a very strong belief that they are pregnant along with some of the physical changes. This condition is known as a false pregnancy
False pregnancy (or pseudocyesis, from the Greek "false" and "pregnancy") is the appearance of clinical or subclinical signs and symptoms associated with pregnancy although the individual is not physically carrying a baby. The mistaken impressi ...
.
Physical signs
Most pregnant women experience a number of symptoms, which can signify pregnancy. A number of early medical sign
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...
s are associated with pregnancy. These signs include:
* the presence of human chorionic gonadotropin
Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo (syncytiotrophoblast initially), which eventually forms the placenta after implantatio ...
(hCG) in the blood and urine
* missed menstrual period
The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The ovarian cycle controls the production and release of eggs ...
* implantation bleeding
Implantation (nidation) is the stage in the embryonic development of mammals in which the blastocyst hatches as the embryo, adheres, and invades into the wall of the female's uterus. Implantation is the first stage of gestation, and when suc ...
that occurs at implantation of the embryo in the uterus during the third or fourth week after last menstrual period
* increased basal body temperature
Basal body temperature (BBT or BTP) is the lowest body temperature attained during rest (usually during sleep). It is usually estimated by a temperature measurement immediately after awakening and before any physical activity has been undertaken. ...
sustained for over two weeks after ovulation
Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilize ...
* Chadwick's sign (darkening of the cervix
The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...
, vagina
In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
, and vulva
The vulva (plural: vulvas or vulvae; derived from Latin for wrapper or covering) consists of the external female sex organs. The vulva includes the mons pubis (or mons veneris), labia majora, labia minora, clitoris, vestibular bulbs, vulv ...
)
* Goodell's sign (softening of the vaginal portion of the cervix)
* Hegar's sign Hegar's sign is a non-sensitive indication of pregnancy in women—its absence does not exclude pregnancy. It pertains to the features of the cervix and the uterine isthmus. It is demonstrated as a softening in the consistency of the uterus, and th ...
(softening of the uterine isthmus
The uterine isthmus is the inferior-posterior part of uterus, on its cervical end — here the uterine muscle ( myometrium) is narrower and thinner. It connects the body and cervix.
The uterine isthmus can become more compressibile in pregnanc ...
)
* Pigmentation
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compoun ...
of the linea alba – linea nigra
Linea nigra (Latin for "black line"), often referred to as a pregnancy line, is a linear hyperpigmentation that commonly appears on the abdomen. The brownish streak is usually about a centimeter (0.4 in) in width. The line runs vertically al ...
, (darkening of the skin in a midline of the abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
, resulting from hormonal changes, usually appearing around the middle of pregnancy).
* Darkening of the nipples and areolas due to an increase in hormones.
Biomarkers
Pregnancy detection can be accomplished using one or more various pregnancy test
A pregnancy test is used to determine whether a female is pregnant or not. The two primary methods are testing for the female pregnancy hormone (human chorionic gonadotropin (hCG)) in blood or urine using a pregnancy test kit, and scanning with ...
s, which detect hormones generated by the newly formed placenta
The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mate ...
, serving as biomarkers
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, pa ...
of pregnancy. Blood and urine tests can detect pregnancy 12 days after implantation. Blood pregnancy tests are more sensitive than urine tests (giving fewer false negatives). Home pregnancy tests are urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellul ...
tests, and normally detect a pregnancy 12 to 15 days after fertilization. A quantitative blood test can determine approximately the date the embryo was conceived because hCG doubles every 36 to 48 hours. A single test of progesterone
Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the majo ...
levels can also help determine how likely a fetus will survive in those with a threatened miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical lo ...
(bleeding in early pregnancy).
Ultrasound
Obstetric ultrasonography
Obstetric ultrasonography, or prenatal ultrasound, is the use of medical ultrasonography in pregnancy, in which sound waves are used to create real-time visual images of the developing embryo or fetus in the uterus (womb). The procedure is a stan ...
can detect fetal abnormalities, detect multiple pregnancies, and improve gestational dating at 24 weeks. The resultant estimated gestational age
In obstetrics, gestational age is a measure of the age of a pregnancy which is taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method if available. Su ...
and due date of the fetus are slightly more accurate than methods based on last menstrual period. Ultrasound is used to measure the nuchal fold in order to screen for Down syndrome
Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual d ...
.
Management
Prenatal care
Pre-conception counseling is care that is provided to a woman or couple to discuss conception, pregnancy, current health issues and recommendations for the period before pregnancy.
Prenatal medical care is the medical and nursing care recommended for women during pregnancy, time intervals and exact goals of each visit differ by country. Women who are high risk have better outcomes if they are seen regularly and frequently by a medical professional than women who are low risk. A woman can be labeled as high risk for different reasons including previous complications in pregnancy, complications in the current pregnancy, current medical diseases, or social issues.
The aim of good prenatal care is prevention, early identification, and treatment of any medical complications. A basic prenatal visit consists of measurement of blood pressure, fundal height
Fundal height, or McDonald's rule, is a measure of the size of the uterus used to assess fetal growth and development during pregnancy. It is measured from the top of the mother's uterus to the top of the mother's pubic symphysis. Fundal height, ...
, weight and fetal heart rate, checking for symptoms of labor, and guidance for what to expect next.
Nutrition
Nutrition
Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficient ...
during pregnancy is important to ensure healthy growth of the fetus. Nutrition during pregnancy is different from the non-pregnant state. There are increased energy requirements and specific micronutrient requirements. Women benefit from education to encourage a balanced energy and protein intake during pregnancy. Some women may need professional medical advice if their diet is affected by medical conditions, food allergies, or specific religious/ ethical beliefs. Further studies are needed to access the effect of dietary advice to prevent gestational diabetes
Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and ...
, although low quality evidence suggests some benefit.Adequate periconceptional (time before and right after conception) folic acid
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing a ...
(also called folate or Vitamin B9) intake has been shown to decrease the risk of fetal neural tube defects, such as spina bifida
Spina bifida (Latin for 'split spine'; SB) is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, men ...
. The neural tube develops during the first 28 days of pregnancy, a urine pregnancy test is not usually positive until 14 days post-conception, explaining the necessity to guarantee adequate folate intake before conception. Folate is abundant in green leafy vegetables, legume
A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock for ...
s, and citrus
''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to ...
. In the United States and Canada, most wheat products (flour, noodles) are fortified with folic acid.
Weight gain
The amount of healthy weight gain during a pregnancy varies. Weight gain is related to the weight of the baby, the placenta, extra circulatory fluid, larger tissues, and fat and protein stores. Most needed weight gain occurs later in pregnancy.
The Institute of Medicine
The National Academy of Medicine (NAM), formerly called the Institute of Medicine (IoM) until 2015, is an American nonprofit, non-governmental organization. The National Academy of Medicine is a part of the National Academies of Sciences, Eng ...
recommends an overall pregnancy weight gain for those of normal weight (body mass index
Body mass index (BMI) is a value derived from the mass ( weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and ...
of 18.5–24.9), of 11.3–15.9 kg (25–35 pounds) having a singleton pregnancy. Women who are underweight (BMI of less than 18.5), should gain between 12.7 and 18 kg (28–40 lb), while those who are overweight
Being overweight or fat is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.
, excess weight reached epidemic proportions globally, with m ...
(BMI of 25–29.9) are advised to gain between 6.8 and 11.3 kg (15–25 lb) and those who are obese
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...
(BMI ≥ 30) should gain between 5–9 kg (11–20 lb). These values reference the expectations for a term pregnancy.
During pregnancy, insufficient or excessive weight gain can compromise the health of the mother and fetus.[ The most effective intervention for weight gain in underweight women is not clear.][ Being or becoming overweight in pregnancy increases the risk of complications for mother and fetus, including ]cesarean section
Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or ...
, gestational hypertension
Gestational hypertension or pregnancy-induced hypertension (PIH) is the development of new hypertension in a pregnant woman after 20 weeks' gestation without the presence of protein in the urine or other signs of pre-eclampsia. Gestational hyperte ...
, pre-eclampsia
Pre-eclampsia is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine. When it arises, the condition begins after 20 weeks of pregnancy. In severe cases of the disease ...
, macrosomia
Large for gestational age (LGA) is a term used to describe infants that are born with an abnormally high weight, specifically in the 90th percentile or above, compared to other babies of the same developmental age. Macrosomia is a similar term tha ...
and shoulder dystocia
Shoulder dystocia is when, after vaginal delivery of the head, the baby's anterior shoulder gets caught above the mother's pubic bone. Signs include retraction of the baby's head back into the vagina, known as "turtle sign". Complications for th ...
.[ Excessive weight gain can make losing weight after the pregnancy difficult.][ Some of these complications are risk factors for ]stroke
A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...
.
Around 50% of women of childbearing age in developed countries like the United Kingdom are overweight or obese before pregnancy. Diet modification is the most effective way to reduce weight gain and associated risks in pregnancy.[
]
Medication
Drugs used during pregnancy can have temporary or permanent effects on the fetus. Anything (including drugs) that can cause permanent deformities in the fetus are labeled as teratogens
Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related ...
. In the U.S., drugs were classified into categories A, B, C, D and X based on the Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
(FDA) rating system to provide therapeutic guidance based on potential benefits and fetal risks. Drugs, including some multivitamins
A multivitamin is a preparation intended to serve as a dietary supplement with vitamins, dietary minerals, and other nutritional elements. Such preparations are available in the form of tablets, capsules, pastilles, powders, liquids, or injectable ...
, that have demonstrated no fetal risks after controlled studies in humans are classified as Category A. On the other hand, drugs like thalidomide
Thalidomide, sold under the brand names Contergan and Thalomid among others, is a medication used to treat a number of cancers (including multiple myeloma), graft-versus-host disease, and a number of skin conditions including complications o ...
with proven fetal risks that outweigh all benefits are classified as Category X.
Recreational drugs
The use of recreational drugs
Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasur ...
in pregnancy can cause various pregnancy complication
Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal d ...
s.
* Alcoholic drinks
An alcoholic beverage (also called an alcoholic drink, adult beverage, or a drink) is a drink that contains ethanol, a type of alcohol that acts as a drug and is produced by fermentation of grains, fruits, or other sources of sugar. The cons ...
consumed during pregnancy can cause one or more fetal alcohol spectrum disorders. According to the CDC
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georg ...
, there is no known safe amount of alcohol during pregnancy and no safe time to drink during pregnancy, including before a woman knows that she is pregnant.
* Tobacco smoking during pregnancy can cause a wide range of behavioral, neurological, and physical difficulties. Smoking during pregnancy causes twice the risk of premature rupture of membranes
Prelabor rupture of membranes (PROM), previously known as premature rupture of membranes, is breakage of the amniotic sac before the onset of labor. Women usually experience a painless gush or a steady leakage of fluid from the vagina. Complicat ...
, placental abruption
Placental abruption is when the placenta separates early from the uterus, in other words separates before childbirth. It occurs most commonly around 25 weeks of pregnancy. Symptoms may include vaginal bleeding, lower abdominal pain, and dang ...
and placenta previa.[Centers for Disease Control and Prevention. 2007]
Preventing Smoking and Exposure to Secondhand Smoke Before, During, and After Pregnancy
. Smoking is associated with 30% higher odds of preterm birth.
* Prenatal cocaine exposure
Prenatal cocaine exposure (PCE), theorized in the 1970s, occurs when a pregnant woman uses cocaine and thereby exposes her fetus to the drug. Babies whose mothers used cocaine while pregnant supposedly have increased risk of several different he ...
is associated with premature birth
Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is between ...
, birth defect
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities ca ...
s and attention deficit disorder
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inap ...
.
* Prenatal methamphetamine exposure can cause premature birth and congenital abnormalities
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can r ...
. Short-term neonatal outcomes in methamphetamine babies show small deficits in infant neurobehavioral function and growth restriction. Long-term effects in terms of impaired brain development may also be caused by methamphetamine
Methamphetamine (contracted from ) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Methamp ...
use.[
* ]Cannabis in pregnancy
Cannabis consumption in pregnancy may or may not be associated with restrictions in growth of the fetus, miscarriage, and cognitive deficits. The American Congress of Obstetricians and Gynecologists recommended that cannabis use be stopped before ...
has been shown to be teratogenic
Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related ...
in large doses in animals, but has not shown any teratogenic effects in humans.
Exposure to toxins
Intrauterine exposure to environmental toxins in pregnancy Environmental toxicants and fetal development is the impact of different toxic substances from the environment on the development of the fetus. This article deals with potential adverse effects of environmental toxicants on the prenatal development ...
has the potential to cause adverse effects on prenatal development
Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal deve ...
, and to cause pregnancy complications
Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal ...
. Air pollution has been associated with low birth weight infants. Conditions of particular severity in pregnancy include mercury poisoning
Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashes ...
and lead poisoning
Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. The brain is the most sensitive. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infertil ...
. To minimize exposure to environmental toxins, the American College of Nurse-Midwives recommends: checking whether the home has lead paint
Lead paint or lead-based paint is paint containing lead. As pigment, lead(II) chromate (, "chrome yellow"), lead(II,IV) oxide, (, "red lead"), and lead(II) carbonate (, "white lead") are the most common forms.. Lead is added to paint to acce ...
, washing all fresh fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...
s and vegetable
Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the edible flower, flowers, ...
s thoroughly and buying organic
Organic may refer to:
* Organic, of or relating to an organism, a living entity
* Organic, of or relating to an anatomical organ
Chemistry
* Organic matter, matter that has come from a once-living organism, is capable of decay or is the product ...
produce, and avoiding cleaning products labeled "toxic" or any product with a warning on the label.
Pregnant women can also be exposed to toxins in the workplace, including airborne particles. The effects of wearing an N95 filtering facepiece respirator are similar for pregnant women as for non-pregnant women, and wearing a respirator for one hour does not affect the fetal heart rate.
Death by violence
Pregnant women or those who have recently given birth in the U.S. are more likely to be murdered than to die from obstetric causes. These homicides are a combination of intimate partner violence and firearms. Health authorities have called the violence "a health emergency for pregnant women," but say that pregnancy-related homicides are preventable if healthcare providers identify those women at risk and offer assistance to them.
Sexual activity
Most women can continue to engage in sexual activity, including sexual intercourse
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal pene ...
, throughout pregnancy. Research suggests that during pregnancy both sexual desire and frequency of sexual relations decrease during the first and third trimester, with a rise during the second trimester. I Sex during pregnancy is a low-risk behavior except when the healthcare provider advises that sexual intercourse be avoided for particular medical reasons. For a healthy pregnant woman, there is no single ''safe'' or ''right'' way to have sex during pregnancy.
Exercise
Regular aerobic exercise
Aerobic exercise (also known as endurance activities, cardio or cardio-respiratory exercise) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. "Aerobic" is defined as "relating to, inv ...
during pregnancy appears to improve (or maintain) physical fitness. Physical exercise
Exercise is a body activity that enhances or maintains physical fitness and overall health and wellness.
It is performed for various reasons, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic s ...
during pregnancy appears to decrease the need for C-section
Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or ...
, and even vigorous exercise carries no significant risks to babies and provides significant health benefits to the mother. Bed rest
Bed rest, also referred to as the rest-cure, is a medical treatment in which a person lies in bed for most of the time to try to cure an illness. Bed rest refers to voluntarily lying in bed as a treatment and not being confined to bed because of ...
, outside of research studies, is not recommended as there is no evidence of benefit and potential harm.
The Clinical Practice Obstetrics Committee of Canada recommends that "All women without contraindications should be encouraged to participate in aerobic and strength-conditioning exercises as part of a healthy lifestyle during their pregnancy". Although an upper level of safe exercise intensity has not been established, women who were regular exercisers before pregnancy and who have uncomplicated pregnancies should be able to engage in high intensity exercise programs, without a higher risk of prematurity, lower birth weight, or gestational weight gain. In general, participation in a wide range of recreational activities appears to be safe, with the avoidance of those with a high risk of falling such as horseback riding or skiing or those that carry a risk of abdominal trauma, such as soccer or hockey.
The American College of Obstetricians and Gynecologists reports that in the past, the main concerns of exercise in pregnancy were focused on the fetus and any potential maternal benefit was thought to be offset by potential risks to the fetus. However, they write that more recent information suggests that in the uncomplicated pregnancy, fetal injuries are highly unlikely. They do, however, list several circumstances when a woman should contact her healthcare provider before continuing with an exercise program: vaginal bleeding, dyspnea
Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...
before exertion, dizziness, headache, chest pain, muscle weakness, preterm labor, decreased fetal movement, amniotic fluid leakage, and calf pain or swelling (to rule out thrombophlebitis
Thrombophlebitis is a phlebitis (inflammation of a vein) related to a thrombus (blood clot). When it occurs repeatedly in different locations, it is known as thrombophlebitis migrans (migratory thrombophlebitis).
Signs and symptoms
The following s ...
).
Sleep
It has been suggested that shift work
Shift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of the week (often abbreviated as '' 24/7''). The practice typically sees the day divided into shifts, set periods of ...
and exposure to bright light at night should be avoided at least during the last trimester of pregnancy to decrease the risk of psychological and behavioral problems in the newborn.
Dental care
The increased levels of progesterone
Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the majo ...
and estrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...
during pregnancy make gingivitis
Gingivitis is a non-destructive disease that causes inflammation of the gums. The most common form of gingivitis, and the most common form of periodontal disease overall, is in response to bacterial biofilms (also called plaque) that is attac ...
more likely; the gums
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue li ...
become edematous, red in colour, and tend to bleed. Also a pyogenic granuloma
A pyogenic granuloma or lobular capillary hemangioma is a vascular tumor that occurs on both mucosa and skin, and appears as an overgrowth of tissue due to irritation, physical trauma, or hormonal factors. It is often found to involve the gum ...
or "pregnancy tumor", is commonly seen on the labial surface of the papilla. Lesions can be treated by local debridement or deep incision depending on their size, and by following adequate oral hygiene
Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems (e.g. bad breath) by regular brushing of the teeth (dental hygiene) and cleaning between the teeth. It is important that oral hygiene be carried ou ...
measures. There have been suggestions that severe periodontitis
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main cau ...
may increase the risk of having preterm birth
Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is betwee ...
and low birth weight
Low birth weight (LBW) is defined by the World Health Organization as a birth weight of an
infant of or less, regardless of gestational age. Infants born with LBW have added health risks which require close management, often in a neonatal int ...
; however, a Cochrane review found insufficient evidence to determine if periodontitis
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main cau ...
can develop adverse birth outcomes.
Flying
In low risk pregnancies, most health care providers approve flying until about 36 weeks of gestational age. Most airlines allow pregnant women to fly short distances at less than 36 weeks, and long distances at less than 32 weeks. Many airlines require a doctor's note that approves flying, especially at over 28 weeks.[ During flights, the risk of ]deep vein thrombosis
Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...
is decreased by getting up and walking occasionally, as well as by avoiding dehydration.Full body scanner
A full-body scanner is a device that detects objects on or inside a person's body for security screening purposes, without physically removing clothes or making physical contact. Unlike metal detectors, full-body scanners can detect non-metal o ...
s do not use ionizing radiation, and are safe in pregnancy.
Pregnancy classes and birth plan
To prepare for the birth of the baby, health care providers recommend that parents attend antenatal classes during the third trimester of pregnancy. Classes include information about the process of labor and birth and the various kinds of births, including both vaginal and caesarean delivery
Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or mo ...
, the use of forceps, and other interventions that may be needed to safely deliver the infant. Types of pain relief, including relaxation techniques, are discussed. Partners or others who may plan to support a woman during her labor and delivery learn how to assist in the birth.
It is also suggested that a birth plan be written at this time. A birth plan is a written statement that outlines the desires of the mother during labor and delivery of the baby. Discussing the birth plan with the midwife or other care provider gives parents a chance to ask questions and learn more about the process of labour.
In 1991 the WHO
Who or WHO may refer to:
* Who (pronoun), an interrogative or relative pronoun
* Who?, one of the Five Ws in journalism
* World Health Organization
Arts and entertainment Fictional characters
* Who, a creature in the Dr. Seuss book '' Horton He ...
launched the Baby-Friendly Hospital Initiative
The Baby Friendly Hospital Initiative (BFHI), also known as Baby Friendly Initiative (BFI), is a worldwide programme of the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF), launched in 1992 in India UNICEFThe Baby- ...
, a global program that recognizes birthing centers and hospitals that offer optimal levels of care for giving birth. Facilities that have been certified as "Baby Friendly" accept visits from expecting parents to familiarize them with the facility and the staff.
Complications
Each year, ill health as a result of pregnancy is experienced (sometimes permanently) by more than 20 million women around the world. In 2016, complications of pregnancy resulted in 230,600 deaths down from 377,000 deaths in 1990.[ Common causes include ]bleeding
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
(72,000), infections
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...
(20,000), hypertensive diseases of pregnancy
Hypertensive disease of pregnancy, also known as maternal hypertensive disorder, is a group of high blood pressure disorders that include preeclampsia, preeclampsia superimposed on chronic hypertension, gestational hypertension, and chronic hyperte ...
(32,000), obstructed labor
Obstructed labour, also known as labour dystocia, is the baby not exiting the pelvis because it is physically block during childbirth although the uterus contracts normally. Complications for the baby include not getting enough oxygen which ma ...
(10,000), and pregnancy with abortive outcome
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ca ...
(20,000), which includes miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemica ...
, abortion
Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pre ...
, and ectopic pregnancy
Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptom ...
.[
The following are some examples of pregnancy complications:
* ]Pregnancy induced hypertension
Gestational hypertension or pregnancy-induced hypertension (PIH) is the development of new hypertension in a pregnant woman after 20 weeks' gestation without the presence of protein in the urine or other signs of pre-eclampsia. Gestational hyperte ...
* Anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...
* Postpartum depression
Postpartum depression (PPD), also called postnatal depression, is a type of mood disorder associated with childbirth, which can affect both sexes. Symptoms may include extreme sadness, low energy, anxiety, crying episodes, irritability, and cha ...
, a common but solvable complication following childbirth that may result from decreased hormonal levels.
* Postpartum psychosis
Postpartum psychosis, also known as puerperal psychosis, involves the abrupt onset of severe mental illness shortly following childbirth. While symptoms of postpartum psychosis have long been observed in mothers, the phenomenon eventually came t ...
* Thromboembolic disorders, with an increased risk due to hypercoagulability in pregnancy. These are the leading cause of death in pregnant women in the US.[
* ]Pruritic urticarial papules and plaques of pregnancy
Pruritic urticarial papules and plaques of pregnancy (PUPPP), known in United Kingdom as polymorphic eruption of pregnancy (PEP), is a chronic hives-like rash that strikes some women during pregnancy. Some skin changes are known to occur in peopl ...
(PUPPP), a skin disease that develops around the 32nd week. Signs are red plaques, papules, and itchiness around the belly button that then spreads all over the body except for the inside of hands and face.
* Ectopic pregnancy
Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptom ...
, including abdominal pregnancy
An abdominal pregnancy is a rare type of ectopic pregnancy where the embryo or fetus is growing and developing outside the womb in the abdomen, but not in the Fallopian tube (usual location), ovary or broad ligament.
Because tubal, ovarian and ...
, implantation of the embryo outside the uterus
* Hyperemesis gravidarum
Hyperemesis gravidarum (HG) is a pregnancy complication that is characterized by severe nausea, vomiting, weight loss, and possibly dehydration. Feeling faint may also occur. It is considered more severe than morning sickness. Symptoms often g ...
, excessive nausea and vomiting that is more severe than normal morning sickness.
* Pulmonary embolism
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream ( embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathin ...
, a blood clot that forms in the legs and migrates to the lungs.
* Acute fatty liver of pregnancy
Acute fatty liver of pregnancy is a rare life-threatening complication of pregnancy that occurs in the third trimester or the immediate period after delivery. It is thought to be caused by a disordered metabolism of fatty acids by mitochondria in ...
is a rare complication thought to be brought about by a disruption in the metabolism of fatty acids by mitochondria
A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ...
.
There is also an increased susceptibility and severity of certain infections in pregnancy.
Miscarriage and stillbirth
Miscarriage is the most common complication of early pregnancy. It is defined as the loss of an embryo or fetus before it is able to survive independently. The most common symptom of miscarriage is vaginal bleeding with or without pain. The miscarriage may be evidenced by a clot-like material passing through and out of the vagina. About 80% of miscarriages occur in the first 12 weeks of pregnancy. The underlying cause in about half of cases involves chromosomal abnormalities.
Stillbirth is defined as fetal death after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without signs of life. Each year about 21,000 babies are stillborn in the U.S. Sadness, anxiety, and guilt may occur after a miscarriage or a stillbirth. Emotional support may help with processing the loss.Fathers may experience grief over the loss as well. A large study found that there is a need to increase the accessibility of support services available for fathers.
Diseases in pregnancy
A pregnant woman may have a pre-existing disease, which is not directly caused by the pregnancy, but may cause complications to develop that include a potential risk to the pregnancy; or a disease may develop during pregnancy.
* Diabetes mellitus and pregnancy
For pregnant women with diabetes, some particular challenges exist for both mother and child. If the pregnant woman has diabetes as a pre-existing disorder, it can cause early labor, birth defects, and larger than average infants. Therefore, e ...
deals with the interactions of diabetes mellitus
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
(not restricted to gestational diabetes
Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and ...
) and pregnancy. Risks for the child include miscarriage, growth restriction, growth acceleration, large for gestational age (macrosomia), polyhydramnios
Polyhydramnios is a medical condition describing an excess of amniotic fluid in the amniotic sac. It is seen in about 1% of pregnancies. It is typically diagnosed when the amniotic fluid index (AFI) is greater than 24 cm.
There are two clini ...
(too much amniotic fluid
The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus, but also serves to facilitate the exchange of nutrients, water, and biochemical products between ...
), and birth defects.
* Thyroid disease in pregnancy Thyroid disease in pregnancy can affect the health of the mother as well as the child before and after delivery. Thyroid disorders are prevalent in women of child-bearing age and for this reason commonly present as a pre-existing disease in pregnan ...
can, if uncorrected, cause adverse effects on fetal and maternal well-being. The deleterious effects of thyroid dysfunction can also extend beyond pregnancy and delivery to affect neurointellectual development in the early life of the child. Demand for thyroid hormones is increased during pregnancy, which may cause a previously unnoticed thyroid disorder to worsen.
* Untreated celiac disease
Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...
can cause a miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemica ...
, intrauterine growth restriction
Intrauterine growth restriction (IUGR), or fetal growth restriction, refers to poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's ...
, small for gestational age, low birthweight
Birth weight is the body weight of a baby at its birth. The average birth weight in babies of European descent is , with the normative range between . On average, babies of South Asian and Chinese descent weigh about . As far as low birth weight ...
and preterm birth
Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is betwee ...
. Often reproductive disorders are the only manifestation of undiagnosed celiac disease and most cases are not recognized. Complications or failures of pregnancy cannot be explained simply by malabsorption
Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...
, but by the autoimmune response
An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly a ...
elicited by the exposure to gluten
Gluten is a structural protein naturally found in certain cereal grains. Although "gluten" often only refers to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grai ...
, which causes damage to the placenta
The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mate ...
. The gluten-free diet
A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats. The incl ...
avoids or reduces the risk of developing reproductive disorders in pregnant women with celiac disease. Also, pregnancy can be a trigger for the development of celiac disease in genetically susceptible women who are consuming gluten.
* Lupus in pregnancy confers an increased rate of fetal death ''in utero,'' miscarriage, and of neonatal lupus
Neonatal lupus erythematosus is an autoimmune disease in an infant born to a mother with anti-Ro/SSA and with or without anti-La/SSB antibodies. The disease most commonly presents with a rash resembling subacute cutaneous lupus erythematosus and ...
.
* Hypercoagulability in pregnancy is the propensity of pregnant women to develop thrombosis
Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (th ...
(blood clots). Pregnancy itself is a factor of hypercoagulability
Thrombophilia (sometimes called hypercoagulability or a prothrombotic state) is an abnormality of blood coagulation that increases the risk of thrombosis (blood clots in blood vessels). Such abnormalities can be identified in 50% of people who ...
(pregnancy-induced hypercoagulability), as a physiologically adaptive mechanism to prevent postpartum bleeding
Postpartum bleeding or postpartum hemorrhage (PPH) is often defined as the loss of more than 500 ml or 1,000 ml of blood following childbirth. Some have added the requirement that there also be signs or symptoms of low blood volume fo ...
.[ However, in combination with an underlying hypercoagulable state, the risk of thrombosis or embolism may become substantial.][Page 264 in: ]
Abortion
An abortion is the termination of an embryo or fetus via medical method. It is usually done within the first trimester, sometimes in the second, and rarely in the third. Reasons for pregnancies being undesired are broad, rape
Rape is a type of sexual assault usually involving sexual intercourse or other forms of sexual penetration carried out against a person without their consent. The act may be carried out by physical force, coercion, abuse of authority, or ...
being the most legally accepted.
Birth control and education
Family planning
Family planning is the consideration of the number of children a person wishes to have, including the choice to have no children, and the age at which they wish to have them. Things that may play a role on family planning decisions include marita ...
, as well as the availability and use of contraception
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr ...
, along with increased comprehensive sex education
Comprehensive sexuality education (CSE) is a sex education instruction method based on-curriculum that aims to give students the knowledge, attitudes, skills, and values to make appropriate and healthy choices in their sexual lives. The intention i ...
, has enabled many to prevent pregnancies when they are not desired. Schemes and funding to support education and the means to prevent pregnancies when they are not intended have been instrumental and are part of the third of the Sustainable Development Goals
The Sustainable Development Goals (SDGs) or Global Goals are a collection of 17 interlinked objectives designed to serve as a "shared blueprint for peace and prosperity for people and the planet, now and into the future".United Nations (2017) R ...
(SDGs) advanced by the United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a centre for harmoni ...
.
Technologies and science
Assisted reproductive technology
Modern reproductive medicine offers many forms of assisted reproductive technology for couples who stay childless against their will, such as fertility medication
Fertility medications, also known as fertility drugs, are medications which enhance reproductive fertility. For women, fertility medication is used to stimulate follicle development of the ovary. There are very few fertility medication options a ...
, artificial insemination
Artificial insemination is the deliberate introduction of sperm into a female's cervix or uterine cavity for the purpose of achieving a pregnancy through in vivo fertilization by means other than sexual intercourse. It is a fertility treatment ...
, ''in vitro'' fertilization and surrogacy
Surrogacy is an arrangement, often supported by a legal agreement, whereby a woman agrees to delivery/labour for another person or people, who will become the child's parent(s) after birth. People may seek a surrogacy arrangement when pregna ...
.
Medical imaging
Medical imaging
Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to re ...
may be indicated
In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. There can be multiple indications to use a procedure or medication. An indication can commonly be confused with the term diagnosis. A diagnosi ...
in pregnancy because of pregnancy complications
Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal ...
, disease, or routine prenatal care
Prenatal care, also known as antenatal care, is a type of preventive healthcare. It is provided in the form of medical checkups, consisting of recommendations on managing a healthy lifestyle and the provision of medical information such as materna ...
. Medical ultrasonography
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, mus ...
including obstetric ultrasonography
Obstetric ultrasonography, or prenatal ultrasound, is the use of medical ultrasonography in pregnancy, in which sound waves are used to create real-time visual images of the developing embryo or fetus in the uterus (womb). The procedure is a stan ...
, and magnetic resonance imaging (MRI) without contrast agents
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiop ...
are not associated with any risk for the mother or the fetus, and are the imaging techniques of choice for pregnant women.[ February 2016] Projectional radiography
Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by x-ray radiation. The image acquisition is generally performed by radiographers, and the images ...
, CT scan and nuclear medicine imaging result in some degree of ionizing radiation
Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...
exposure, but in most cases the absorbed dose
Absorbed dose is a dose quantity which is the measure of the energy deposited in matter by ionizing radiation per unit mass. Absorbed dose is used in the calculation of dose uptake in living tissue in both radiation protection (reduction of harmf ...
s are not associated with harm to the baby.[ At higher dosages, effects can include ]miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemica ...
, birth defect
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities ca ...
s and intellectual disability
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation,Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signifi ...
.[
]
Epidemiology
About 213 million pregnancies occurred in 2012 of which 190 million were in the developing world
A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreeme ...
and 23 million were in the developed world.[ This is about 133 pregnancies per 1,000 women aged 15 to 44.] About 10% to 15% of recognized pregnancies end in miscarriage.[ Globally, 44% of pregnancies are ]unplanned
''Unplanned'' is a 2019 American drama film written and directed by Cary Solomon and Chuck Konzelman. It is based on the disputed 2011 memoir ''Unplanned'' by anti-abortion activist Abby Johnson. The film stars Ashley Bratcher as Johnson, foll ...
. Over half (56%) of unplanned pregnancies are aborted. In countries where abortion is prohibited, or only carried out in circumstances where the mother's life is at risk, 48% of unplanned pregnancies are aborted illegally. Compared to the rate in countries where abortion is legal, at 69%.
Of pregnancies in 2012, 120 million occurred in Asia, 54 million in Africa, 19 million in Europe, 18 million in Latin America and the Caribbean, 7 million in North America, and 1 million in Oceania
Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...
.[ Pregnancy rates are 140 per 1000 women of childbearing age in the developing world and 94 per 1000 in the developed world.][
The rate of pregnancy, as well as the ages at which it occurs, differ by country and region. It is influenced by a number of factors, such as cultural, social and religious norms; access to contraception; and rates of education. The ]total fertility rate
The total fertility rate (TFR) of a population is the average number of children that would be born to a woman over her lifetime if:
# she were to experience the exact current age-specific fertility rates (ASFRs) through her lifetime
# she were t ...
(TFR) in 2013 was estimated to be highest in Niger
)
, official_languages =
, languages_type = National languages[Singapore
Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...](_blank)
(0.79 children/woman).
In Europe, the average childbearing age has been rising continuously for some time. In Western, Northern, and Southern Europe, first-time mothers are on average 26 to 29 years old, up from 23 to 25 years at the start of the 1970s. In a number of European countries (Spain), the mean age of women at first childbirth has crossed the 30-year threshold.
This process is not restricted to Europe. Asia, Japan and the United States are all seeing average age at first birth on the rise, and increasingly the process is spreading to countries in the developing world like China, Turkey and Iran. In the US, the average age of first childbirth was 25.4 in 2010.
In the United States and United Kingdom, 40% of pregnancies are unplanned
''Unplanned'' is a 2019 American drama film written and directed by Cary Solomon and Chuck Konzelman. It is based on the disputed 2011 memoir ''Unplanned'' by anti-abortion activist Abby Johnson. The film stars Ashley Bratcher as Johnson, foll ...
, and between a quarter and half of those unplanned pregnancies were unwanted pregnancies.
In the US, a woman's educational attainment and her marital status are correlated with childbearing: the percentage of women unmarried at the time of first birth drops with increasing educational level. In other words: among uneducated women, a large fraction (~80%) have their first child while they are unmarried. By contrast, few women with a bachelor's degree or higher (~25%) have their first child while unmarried. However, this phenomenon also has a strong generational component: in 1996, about 50% of women without a university degree had their first child being unmarried while that number increased to ~85% in 2018. Similarly, in 1996, only 4% of women with a BA degree or similar had their first child being unmarried. In 2018, that fraction increased to ~25%.
Legal and social aspects
Legal protection
Many countries have various legal regulations in place to protect pregnant women and their children. Many countries have laws against pregnancy discrimination
Pregnancy discrimination is a type of employment discrimination that occurs when expectant women are fired, not hired, or otherwise discriminated against due to their pregnancy or intention to become pregnant. Common forms of pregnancy discriminat ...
.
Maternity Protection Convention ensures that pregnant women are exempt from activities such as night shifts or carrying heavy stocks. Maternity leave
Parental leave, or family leave, is an employee benefit available in almost all countries. The term "parental leave" may include maternity, Paternity (law), paternity, and adoption leave; or may be used distinctively from "maternity leave" and ...
typically provides paid leave from work during roughly the last trimester of pregnancy and for some time after birth. Notable extreme cases include Norway (8 months with full pay) and the United States (no paid leave at all except in some states).
In the United States, some actions that result in miscarriage or stillbirth, such as beating a pregnant woman, are considered crimes. One law that does so is the federal Unborn Victims of Violence Act
The Unborn Victims of Violence Act of 2004 (Public Law 108-212) is a United States law that recognizes an embryo or fetus in utero as a legal victim, if they are injured or killed during the commission of any of over 60 listed federal crimes of ...
. In 2014, the American state of Tennessee
Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...
passed a law which allows prosecutors to charge a woman with criminal assault if she uses illegal drugs during her pregnancy and her fetus or newborn is harmed as a result.
However, protections are not universal. In Singapore
Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...
, the ''Employment of Foreign Manpower Act'' forbids current and former work permit holders from becoming pregnant or giving birth in Singapore without prior permission. Violation of the Act is punishable by a fine of up to S$10,000 (US$) and deportation
Deportation is the expulsion of a person or group of people from a place or country. The term ''expulsion'' is often used as a synonym for deportation, though expulsion is more often used in the context of international law, while deportation ...
, and until 2010, their employers would lose their $5,000 security bond.
Teenage pregnancy
Teenage pregnancy
Teenage pregnancy, also known as adolescent pregnancy, is pregnancy in a female adolescent or young adult under the age of 20. This includes those who are legally considered adults in their country. The WHO defines adolescence as the period bet ...
is also known as adolescent pregnancy. The WHO
Who or WHO may refer to:
* Who (pronoun), an interrogative or relative pronoun
* Who?, one of the Five Ws in journalism
* World Health Organization
Arts and entertainment Fictional characters
* Who, a creature in the Dr. Seuss book '' Horton He ...
defines adolescence as the period between the ages of 10 and 19 years. Adolescents face higher health risks than women who give birth at age 20 to 24 and their infants are at a higher risk for preterm birth, low birth weight, and other severe neonatal conditions. Their children continue to face greater challenges, both behavioral and physical, throughout their lives. Teenage pregnancies are also related to social issues, including social stigma, lower educational levels, and poverty. Studies show that female adolescents are often in abusive relationships at the time of their conceiving.
Nurse-Family Partnership
Nurse-Family Partnership (NFP) is a non-profit organization operating in the United States that connects mothers pregnant with their first child with registered nurses, who provide home visits until the child's second birthday. NFP interventio ...
(NFP) is a non-profit organization operating in the United States and the UK designed to serve the needs of low income young mothers who may have special needs in their first pregnancy. Each mother served is partnered with a registered nurse early in her pregnancy and receives ongoing nurse home visits that continue through her child's second birthday. NFP intervention has been associated with improvements in maternal health, child health, and economic security.
Racial disparities
There are significant racial imbalances in pregnancy and neonatal care systems. Midwifery guidance, treatment, and care have been related to better birth outcomes. Diminishing racial inequities in health is an increasingly large public health challenge in the United States. Despite the fact that average rates have decreased, data on neonatal mortality demonstrates that racial disparities have persisted and grown. The death rate for African American babies is nearly double that of white neonates. According to studies, congenital defects
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
, SIDS
Sudden infant death syndrome (SIDS) is the sudden unexplained death of a child of less than one year of age. Diagnosis requires that the death remain unexplained even after a thorough autopsy and detailed death scene investigation. SIDS usual ...
, preterm birth
Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is betwee ...
, and low birth weight
Low birth weight (LBW) is defined by the World Health Organization as a birth weight of an
infant of or less, regardless of gestational age. Infants born with LBW have added health risks which require close management, often in a neonatal int ...
are all more common among African American babies.
Midwifery care has been linked to better birth and postpartum outcomes for both mother and child. It caters to the needs of the woman and provides competent, sympathetic care, and is essential for maternal health improvement. The presence of a doula
A doula () is a trained professional who provides expert guidance for the service of others and who supports another person (the doula's client) through a significant health-related experience, such as childbirth, miscarriage, induced abortion o ...
, or birth assistant, during labor and delivery, has also been associated with improved levels of satisfaction with medical birth care. Providers recognized their profession from a historical standpoint, a link to African origins, the diaspora, and prevailing African American struggles. Providers participated in both direct clinical experience and activist involvement. Advocacy efforts aimed to enhance the number of minority birth attendants and to promote the benefits of woman-centered birth care to neglected areas.
Transgender people
Transgender people have experienced significant advances in societal acceptance in recent years leaving many health professionals unprepared to provide quality care. A 2015 report suggests that "numbers of transgender individuals who are seeking family planning, fertility, and pregnancy services could certainly be quite large".
Regardless of prior hormone replacement therapy treatments, the progression of pregnancy and birthing procedures for transgender people who carry pregnancies are typically the same as those of cisgender
Cisgender (often shortened to cis; sometimes cissexual) is a term used to describe a person whose gender identity corresponds to their sex assigned at birth. The word ''cisgender'' is the antonym of ''transgender''. The prefix ''wiktionary:cis ...
women however, they may be subjected to discrimination, which can include a variety of negative social, emotional, and medical experiences, as pregnancy is regarded as an exclusively female activity. According to a study by the American College of Obstetricians and Gynecologists
The American College of Obstetricians and Gynecologists (ACOG) is a professional association of physicians specializing in obstetrics and gynecology in the United States. Several Latin American countries are also represented within Districts of ...
, there is a lack of awareness, services, and medical assistance available to pregnant trans men.
Culture
In most cultures, pregnant women have a special status in society and receive particularly gentle care.[ At the same time, they are subject to expectations that may exert great psychological pressure, such as having to produce a son and heir. In many traditional societies, pregnancy must be preceded by marriage, on pain of ostracism of mother and (illegitimate) child.
Overall, pregnancy is accompanied by numerous customs that are often subject to ethnological research, often rooted in ]traditional medicine
Traditional medicine (also known as indigenous medicine or folk medicine) comprises medical aspects of traditional knowledge that developed over generations within the folk beliefs of various societies, including indigenous peoples, before the ...
or religion. The baby shower
A baby shower is a party of gift-giving, drinking beers or a ceremony that has different names in different cultures. It celebrates the delivery or expected birth of a child or the transformation of a woman into a mother.
Etymology
The term ''s ...
is an example of a modern custom.
Pregnancy is an important topic in sociology of the family
Sociology of the family is a subfield of the subject of sociology, in which researchers and academics study family structure as a social institution and unit of socialization from various sociological perspectives. It can be seen as an example of ...
. The prospective child may preliminarily be placed into numerous social role
A role (also rôle or social role) is a set of connected behaviors, rights, obligations, beliefs, and norms as conceptualized by people in a social situation. It is an expected or free or continuously changing behavior and may have a given indivi ...
s. The parents' relationship and the relation between parents and their surroundings are also affected.
A belly cast
A belly cast is a three-dimensional plaster sculpture of a woman's pregnant abdomen as a keepsake of her pregnancy. It can also be known as a belly mask, pregnancy belly cast, a pregnant plaster cast, or prenatal cast.
Belly casts are most often ...
may be made during pregnancy as a keepsake.
Arts
Images of pregnant women, especially small figurine
A figurine (a diminutive form of the word ''figure'') or statuette is a small, three-dimensional sculpture that represents a human, deity or animal, or, in practice, a pair or small group of them. Figurines have been made in many media, with cl ...
s, were made in traditional cultures in many places and periods, though it is rarely one of the most common types of image. These include ceramic figures from some Pre-Columbian
In the history of the Americas, the pre-Columbian era spans from the original settlement of North and South America in the Upper Paleolithic period through European colonization, which began with Christopher Columbus's voyage of 1492. Usually, th ...
cultures, and a few figures from most of the ancient Mediterranean cultures. Many of these seem to be connected with fertility
Fertility is the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Fertili ...
. Identifying whether such figures are actually meant to show pregnancy is often a problem, as well as understanding their role in the culture concerned.
Among the oldest surviving examples of the depiction of pregnancy are prehistoric figurines found across much of Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...
and collectively known as Venus figurines
A Venus figurine is any Upper Palaeolithic statuette portraying a woman, usually carved in the round.Fagan, Brian M., Beck, Charlotte, "Venus Figurines", ''The Oxford Companion to Archaeology'', 1996, Oxford University Press, pp. 740–741 Mos ...
. Some of these appear to be pregnant.
Due to the important role of the Mother of God
''Theotokos'' (Greek: ) is a title of Mary, mother of Jesus, used especially in Eastern Christianity. The usual Latin translations are ''Dei Genitrix'' or ''Deipara'' (approximately "parent (fem.) of God"). Familiar English translations are " ...
in Christianity
Christianity is an Abrahamic monotheistic religion based on the life and teachings of Jesus of Nazareth. It is the world's largest and most widespread religion with roughly 2.38 billion followers representing one-third of the global pop ...
, the Western visual arts have a long tradition of depictions of pregnancy, especially in the biblical scene of the Visitation, and devotional images called a ''Madonna del Parto
A Madonna del Parto ("Madonna of Parturition") is an iconic depiction of the Virgin Mary shown as pregnancy, pregnant, which was developed in Italy, mainly in Tuscany in the 14th century. Examples include works by Taddeo Gaddi, Bernardo Daddi and N ...
''.
The unhappy scene usually called ''Diana and Callisto'', showing the moment of discovery of Callisto Callisto most commonly refers to:
*Callisto (mythology), a nymph
*Callisto (moon), a moon of Jupiter
Callisto may also refer to:
Art and entertainment
*''Callisto series'', a sequence of novels by Lin Carter
*''Callisto'', a novel by Torsten Kro ...
's forbidden pregnancy, is sometimes painted from the Renaissance onwards. Gradually, portraits of pregnant women began to appear, with a particular fashion for "pregnancy portraits" in elite portraiture of the years around 1600.
Pregnancy, and especially pregnancy of unmarried women, is also an important motif in literature. Notable examples include Thomas Hardy
Thomas Hardy (2 June 1840 – 11 January 1928) was an English novelist and poet. A Victorian realist in the tradition of George Eliot, he was influenced both in his novels and in his poetry by Romanticism, including the poetry of William Word ...
's 1891 novel '' Tess of the d'Urbervilles'' and Goethe's 1808 play ''Faust
Faust is the protagonist of a classic German legend based on the historical Johann Georg Faust ( 1480–1540).
The erudite Faust is highly successful yet dissatisfied with his life, which leads him to make a pact with the Devil at a crossroads ...
''.
See also
* Couvade syndrome
Couvade syndrome, also called sympathetic pregnancy, is a proposed condition in which an expectant father experiences some of the same symptoms and behavior as his pregnant partner. These most often include major weight gain, altered hormone level ...
* Cryptic pregnancy
The term cryptic pregnancy is used by medical professionals to describe a pregnancy that is not recognized by the woman who is pregnant until she is in labor or has given birth. The term is also used online for a special form of false pregnancy (ps ...
* False pregnancy
False pregnancy (or pseudocyesis, from the Greek "false" and "pregnancy") is the appearance of clinical or subclinical signs and symptoms associated with pregnancy although the individual is not physically carrying a baby. The mistaken impressi ...
* Simulated pregnancy
A simulated pregnancy is a deliberate attempt to create the impression of pregnancy.
It should not be confused with false pregnancy, where a person mistakenly believes that they are pregnant.
Techniques
People who wish to ''look'' pregnant, gen ...
References
Further reading
*
*
*
External links
*
Merck Manual Home Health Handbook
– further details on the diseases, disorders, etc., which may complicate pregnancy.
Pregnancy care
– NHS guide to having a baby including preconception, pregnancy, labor, and birth.
{{Authority control
Birth control
Family
Fertility
Human female endocrine system
Obstetrics
Wikipedia medicine articles ready to translate
Women's health
Maternal health
Articles containing video clips