TheInfoList

Pregnancy, also known as gestation, is the time during which one or more
offspring In biology, offspring are the young creation of living organisms, produced either by a Asexual reproduction, single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a more ...

develops inside a
woman A woman is an adult . Prior to adulthood, a female human is referred to as a (a female or ). The plural ''women'' is sometimes used in certain phrases such as "" to denote female humans regardless of age. Typically, women have two s and ar ...

. A
multiple pregnancy A multiple birth is the culmination of one multiple pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, ...
involves more than one offspring, such as with
twin Twins are two offspring In biology, offspring are the young born of living organism, 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 ...

s. Pregnancy usually occurs by
sexual intercourse Sexual intercourse (or coitus or copulation) is a sexual activity Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality Human sexuality is the way ...

, 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, intracytoplasmic sperm injection (ICSI), cryopreservation of gametes or embryo ...
procedures. A pregnancy may end in a live birth, a spontaneous
miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the natural loss of an embryo or fetus before it is fetal viability, able to survive independently. Some use the cutoff of 20 weeks of gestation, after whi ...
, an
induced abortion Abortion is the ending of a pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, such as with twin ...
, or a
stillbirth Stillbirth is typically defined as fetal A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring of an animal that develops from an embryo An embryo is the early stage of development of a multicellular or ...
.
Childbirth Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing through the vagina or by Caesarean section. In 2015, there were about 135 million births globally. About 15 million ...

typically occurs around 40 weeks from the start of the
last menstrual period Menstruation (also known as a period and many other colloquial Colloquialism or colloquial language is the style (sociolinguistics), linguistic style used for casual (informal) communication. It is the most common functional style of speech, ...
(LMP). This is just over nine months (
gestational age Gestational age is a measure of the age of a pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, such as w ...
). When using
fertilization age Illustration depicting ovulation and fertilization. Human fertilization is the union of a human egg and sperm Sperm is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there ...
, the length is about 38 weeks. An
embryo An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism that consists of more than one cell (biology), cell, in contrast to a unicellular organism. All species of animals, Embryophyte, la ...

is the developing offspring during the first eight weeks following fertilization, (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 An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism tha ...

'' 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 Symptoms and discomforts of pregnancy , symptom of pregnancy that involves nausea or vomiting. Despite the name, nausea or vomiting can occur at any time during the day. T ...

(nausea and vomiting), hunger, and frequent urination. Pregnancy may be confirmed with a
pregnancy test A pregnancy test is used to determine whether a woman is pregnant Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspri ...

. Pregnancy is divided into three trimesters of approximately 3 months each. The
first trimester Pregnancy, also known as gestation, is the time during which one or more offspring In biology, offspring are the young born of living organism, organisms, produced either by a single organism or, in the case of sexual reproduction, two orga ...
includes conception, which is when the sperm fertilizes the egg. The
fertilized egg A zygote (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately 10.7 mi ...

then travels down the
Fallopian tube The Fallopian tubes, also known as uterine tubes, salpinges (singular salpinx), or oviducts, are tubes that stretch from the ovaries The ovary is an organ found in the female reproductive system that produces an ovum. When released, this tra ...

and attaches to the inside of the
uterus The uterus (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

, where it begins to form the
embryo An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism that consists of more than one cell (biology), cell, in contrast to a unicellular organism. All species of animals, Embryophyte, la ...

and
placenta The placenta is a temporary fetal that begins developing from the shortly after . It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important pro ...

. 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. Prenatal care may include taking extra
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 and s ...

, avoiding
drugs A drug is any that causes a change in an organism's or when consumed. Drugs are typically distinguished from and substances that provide nutritional support. Consumption of drugs can be via , , , , via a on the skin, , or . In , a drug ...
,
tobacco smoking Tobacco smoking is the practice of burning tobacco Tobacco is the common name of several plants in the ' of the , and the general term for any product prepared from the of these plants. of tobacco are known, but the chief commerci ...

, and alcohol, taking regular exercise, having
blood test A blood test is a laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which science, scientific or technological research, experiments, and measurement may be performed. Laboratory services a ...

s, and regular
physical examination In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient A patient is any recipient of health care Health care, health-care, or healthcare is the maintenance or improvement of health ...

s.
Complications of pregnancy Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the u ...
may include disorders of high blood pressure,
gestational diabetes Gestational diabetes is a condition in which a woman without diabetes Diabetes mellitus (DM), commonly known as diabetes, is a group of metabolic disorders characterized by a high blood sugar level over a prolonged period of time. Symptoms of ...
,
iron-deficiency anemia Iron-deficiency anemia is anemia Anemia ( also spelled anaemia) is a decrease in the total amount of red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus i ...
, 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 Preterm birth, also known as premature birth, is the Childbirth, birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Very early preterm birth is before 32 weeks, early preterm birth ...
" and at higher risk of health problems such as
cerebral palsy Cerebral palsy (CP) is a group of movement disorders Movement disorders are clinical syndromes with either an excess of movement or a paucity of voluntary and involuntary movements, unrelated to weakness or spasticity. Movement disorders are sy ...

. 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 Delivery may refer to: *Delivery (commerce), of goods, e.g.: **Pizza delivery **Milk delivery Film and television *Delivering (film), ''Delivering'' (film), a 1993 short film by Todd Field *Delivery (film), ''Delivery'' (film), a 2005 animated sho ...

before 39 weeks by
labor induction Labor induction is the process or treatment that stimulates childbirth Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing through the vagina or by Caesarean section. ...
or
caesarean section Caesarean section, also known as C-section, or caesarean delivery, is the surgical procedure Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical or dental s ...
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 Image:Imf-advanced-un-least-developed-2008.svg, 450px, Example of Older Classifications by the International Monetary Fund, IMF and the United Nations, UN from 2008 A developing country is a country with a less developed Industrial sector, i ...
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. In 2016, complications of pregnancy resulted in 230,600 maternal deaths, down from 377,000 deaths in 1990. Common causes include
bleeding Bleeding, also known as a hemorrhage, haemorrhage, or simply blood loss, is blood Blood is a body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substan ...
,
infections An infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host A host is a person responsible for guests at an event or for providing hospitality during it. Host may ...
, hypertensive diseases of pregnancy,
obstructed labor Obstructed labour, also known as labour dystocia, is when the baby does not exit the pelvis during childbirth Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing thro ...
, miscarriage, abortion, or
ectopic pregnancy Ectopic pregnancy is a complication 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 p ...

. Globally, 44% of pregnancies are
unplanned ''Unplanned'' is a 2019 American drama Drama is the specific Mode (literature), mode of fiction Mimesis, represented in performance: a Play (theatre), play, opera, mime, ballet, etc., performed in a theatre, or on Radio drama, radio or tele ...
. 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 a method or device used to prevent pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woma ...
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 A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with") is "an appa ...

word meaning "heavy" and a pregnant female is sometimes referred to as a ''gravida''. '' Gravidity'' refers to the number of times that a female has been pregnant. Similarly, the term '''' 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 emb ...

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'' 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 ending of a pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring In biology, offspring are the young born of living organism, organisms, produced either by a single organism ...

s,
miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the natural loss of an embryo or fetus before it is fetal viability, able to survive independently. Some use the cutoff of 20 weeks of gestation, after whi ...
s and/or
stillbirth Stillbirth is typically defined as fetal A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring of an animal that develops from an embryo An embryo is the early stage of development of a multicellular or ...
s account for parity values being less than the gravida number. In the case of a
multiple birth A multiple birth is the culmination of one multiple pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, ...
the gravida number and parity value are increased by one only. 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

The usual
signs and symptoms of pregnancy The signs and symptoms of pregnancy are those presentations and conditions that result from pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregn ...
do not significantly interfere with
activities of daily living Activities of daily living (ADLs or ADL) is a term used in healthcare to refer to people's daily self-care Self care is the individual practise of health management without the aid of a medical professional. In health care, self-care is an ...
or pose a health-threat to the mother or baby. However,
pregnancy complications Complications of pregnancy are health problems that are related to pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than on ...
can cause other more severe symptoms, such as those associated with
anemia Anemia ( anaemia) is a decrease in the total amount of s (RBCs) or in the , or a lowered ability of the blood to carry . When anemia comes on slowly, the symptoms are often vague and may include , weakness, , and a poor ability to exercise. W ...

. Common signs and symptoms of pregnancy include: *
Tiredness Fatigue is a feeling of tiredness. It may be sudden or gradual in onset. It is a normal phenomenon if it follows prolonged physical or mental activity, and resolves completely with rest. However, it may be a symptom of a medical condition if it ...
*
Morning sickness Morning sickness, also called nausea and vomiting of pregnancy (NVP), is a Symptoms and discomforts of pregnancy , symptom of pregnancy that involves nausea or vomiting. Despite the name, nausea or vomiting can occur at any time during the day. T ...

*
Constipation Constipation refers to bowel movements that are 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 movement. Complications ...
*
Pelvic girdle pain Pelvic girdle pain (abbreviated PGP) can be described as a Symptoms and discomforts of pregnancy, pregnancy discomfort for some women and a severe disability for others. PGP can cause Chronic pain, pain, instability and limitation of mobility and f ...
*
Back pain Back pain is pain felt in the back. Back pain is divided into 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 are ...

*
Braxton Hicks contractions Braxton Hicks contractions, also known as practice contractions, are sporadic uterine contractions that may start around six weeks into a pregnancy. However, they are usually felt in the second The second (symbol: s, abbreviation: sec) is t ...
. 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 Limb (anatomy), limbs. In the most dependent parts of the body (those hanging distally), it may be called ...
swelling of the lower limbs. Common complaint in advancing pregnancy. Can be caused by inferior vena cava syndrome resulting from compression of the
inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood Blood is a body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance th ...

and pelvic veins by the
uterus The uterus (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

hydrostatic pressure Fluid statics or hydrostatics is the branch of fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics Mechanics (Ancient Greek, Greek: ) is the area of physics concerned with the motions of physical object ...

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 dia ...
often caused by compression of both the inferior vena cava and the
abdominal aorta 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 diaphragm (anatomy), diaphragm, ...

( aortocaval compression syndrome). * Increased urinary frequency. A common complaint, caused by increased intravascular volume, elevated
glomerular filtration rate Renal functions include maintaining an acid–base balance An acid dissociation constant, ''K''a, (also known as acidity constant, or acid-ionization constant) is a quantitative measure of the strength of an acid An acid is a molecu ...
, and compression of the
bladder The urinary bladder, or simply bladder, is a hollow muscular organ in humans and other vertebrates that stores urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ure ...
by the expanding uterus. *
Urinary tract infection A urinary tract infection (UTI) is an infection An infection is the invasion of an organism's body Tissue (biology), tissues by Pathogen, disease-causing agents, their multiplication, and the reaction of host (biology), host tissues to the ...

*
Varicose veins Varicose veins, also known as varicoses, are a medical condition in which superficial vein A superficial vein is a vein that is close to the surface of the body. This differs from deep veins that are far from the surface. Superficial veins are ...

. Common complaint caused by relaxation of the venous
smooth muscle Smooth muscle is an involuntary non-striated muscle Striated muscle tissue is a muscle tissue Muscle tissue is a soft tissue that composes muscles in animal bodies, and gives rise to muscles' ability to contract. It is also referred to as myo ...

and increased intravascular pressure. *
Hemorrhoids Hemorrhoids, also spelled haemorrhoids, are vascular structures in the anal canal The anal canal is the terminal segment of the large intestine, between the rectum and anus, located below the level of the pelvic diaphragm. It is located withi ...

(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. The discomfort often rises in the chest and may radiate to the neck, throat, or angle of the arm. Heartbur ...
, and
nausea Nausea is a diffuse sensation of unease and discomfort, often perceived as an urge to vomiting, vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, upper abdomen, or ...

. *
Stretch marks :''"Striae :''" Striae" is also a general term referring to thin, narrow grooves or channels, or a thin line or band especially if several of them are parallel or close together.'' Stretch marks, also known as Striae or Striae distensae, are ...

*
Breast tenderness Breast pain is the symptom of discomfort in the breast The breast is one of two prominences located on the upper ventral region of the torso of primates. In females, it serves as the mammary gland, which produces and secretes milk to feed ...
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 222px, Joseph Scaliger's ''De emendatione temporum'' (1583) began the modern science of chronology Chronology (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European language ...
of pregnancy is, unless otherwise specified, generally given as
gestational age Gestational age is a measure of the age of a pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, such as w ...
, where the starting point is the beginning of the woman's
last menstrual period Menstruation (also known as a period and many other colloquial Colloquialism or colloquial language is the style (sociolinguistics), linguistic style used for casual (informal) communication. It is the most common functional style of speech, ...
(LMP), or the corresponding age of the gestation as estimated by a more accurate method if available. Sometimes, timing may also use the
fertilization age Illustration depicting ovulation and fertilization. Human fertilization is the union of a human egg and sperm Sperm is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there ...
which is the age of the embryo.

## Start of gestational age

The
American Congress of Obstetricians and Gynecologists The American College of Obstetricians and Gynecologists 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 the orga ...
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 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 the orga ...
. Created November 2012.
* Directly calculating the days since the beginning of the
last menstrual period Menstruation (also known as a period and many other colloquial Colloquialism or colloquial language is the style (sociolinguistics), linguistic style used for casual (informal) communication. It is the most common functional style of speech, ...

. * Early
obstetric ultrasound Obstetric ultrasonography, or prenatal ultrasound, is the use of medical ultrasonography Medical ultrasound (also known as diagnostic sonography or ultrasonography) is a medical imaging, diagnostic imaging technique, or therapeutic ultrasound, ...
, comparing the size of an
embryo An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism that consists of more than one cell (biology), cell, in contrast to a unicellular organism. All species of animals, Embryophyte, la ...

or
fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism tha ...

to that of a
reference group In the social sciences, types of social groups refers to the categorization of relationships identified within social group In the social sciences, a social group can be defined as two or more people who interact with one another, share simil ...
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 In vitro fertilisation (IVF) is a process of fertilisation 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 in ...

, calculating days since
oocyte retrievalTransvaginal oocyte retrieval (TVOR), also referred to as oocyte retrieval (OCR), is a technique used in in vitro fertilization (IVF) in order to remove oocytes from the ovary The ovary is an organ found in the female reproductive system that pr ...
or
co-incubation In vitro fertilisation (IVF) is a process of fertilisation where an ovum, egg is combined with spermatozoon, sperm outside the body, in vitro ("in glass"). The process involves monitoring and stimulating a woman's Ovulation cycle, ovulatory pr ...

## Trimesters

Pregnancy is divided into three trimesters, each lasting for approximately 3 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 or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing through the vagina or by Caesarean section. In 2015, there were about 135 million births globally. About 15 million ...

.

## 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 * , a Wolverine comic book mini-series published by Marvel Comics in 2002 * , a 1999 ''Buffy the Vampire Slayer'' comic book series * , a major ''Judge Dred ...
for
gestational age Gestational age is a measure of the age of a pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, such as w ...
, 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. ''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, also referred to as a mobile app or simply an app, is a computer program In imperative programming In computer science, imperative programming is a programming paradigm that uses Statement (computer science), statements t ...
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 year) is a that contains an additional day (or, in the case of a , a month) added to keep the calendar year synchronized with the or . Because astronomical events and seasons do not repeat in a ...

, 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 statistical dispersion, 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 v ...

of 14 days when gestational age is estimated by first trimester
ultrasound Ultrasound is s with higher than the upper audible limit of human . Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is appro ...
, and 16 days when estimated directly by last menstrual period.

# Physiology

## 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, puberty, pubertal maturatio ...
that stimulates
folliculogenesis :''Although the process is similar in many animals, this article will deal exclusively with human Humans (''Homo sapiens'') are the most populous and widespread species of primates, characterized by bipedality, opposable thumbs, hairlessness, ...
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. O ...

creates a mature
egg cell The egg cell, or ovum (plural ova), is the female reproductive Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproducti ...
, the female
gamete A gamete ( /ˈɡæmiːt/; from Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the foll ...
.
Fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise.2C -ize .28-isation.2C -ization.29, spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes ...

is the event where the egg cell fuses with the male gamete,
spermatozoon A spermatozoon (pronounced , alternate spelling spermatozoön; plural spermatozoa; from grc, σπέρμα ("seed") and grc, ζῷον ("living being")) is a motile Motility is the ability of an organism In biology, an organism (from An ...
. 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 Eukaryotes () are organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are c ...

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 Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality Human sexuality is the way ...

. Pregnancy rates for sexual intercourse are highest during the
menstrual cycle The menstrual cycle is a series of natural changes in hormone A hormone (from the Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country l ...

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, intracytoplasmic sperm injection (ICSI), cryopreservation of gametes or embryo ...
such as artificial insemination and
in vitro fertilisation In vitro fertilisation (IVF) is a process of fertilisation Fertilisation or fertilization (see American and British English spelling differences#-ise.2C -ize .28-isation.2C -ization.29, spelling differences), also known as generative f ...
. Fertilization (conception) is sometimes used as the initiation of pregnancy, with the derived age being termed
fertilization age Illustration depicting ovulation and fertilization. Human fertilization is the union of a human egg and sperm Sperm is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there ...
. 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 found in the female reproductive system 400px, 1. Labia_majora.html"_;"title="Vulva: 2. Labia_majora">Vulva: 2. Labia_majora; 3. Labia_minora; 4. Vulval_vestibule.html" ;"title="Labia_minora.html" ...

, unite in one of the two
Fallopian tube The Fallopian tubes, also known as uterine tubes, salpinges (singular salpinx), or oviducts, are tubes that stretch from the ovaries The ovary is an organ found in the female reproductive system that produces an ovum. When released, this tra ...

s. The fertilized egg, known as a
zygote A zygote (, ) is a eukaryotic Eukaryotes () are organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are c ...

, 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 development of mammal Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in th ...

. The blastocyst arrives at the uterus and attaches to the uterine wall, a process known as
implantation Implantation may refer to: * Implantation (human embryo), in which the human embryo adheres to the wall of the uterus * Implant (medicine), insertion of implants * Endometrial transplantation, as part of the Endometriosis, theory of retrograde mens ...
. The development of the mass of cells that will become the infant is called
embryogenesis An embryo is the early stage of development of a . In general, in s that , embryonic development is the part of the life cycle that begins just after and continues through the formation of body structures, such as tissues and organs. Each embr ...

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 fetal that begins developing from the shortly after . It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important pro ...

and
umbilical cord In placental Placentalia is one of the three extant subdivisions of the class of animals Mammalia Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European la ...
. 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 An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism tha ...

. 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 A brain is an organ that serves as the center of the nervous system In Biology, biology, the nervous system is a Complex system, highly complex part of an animal that coordinates its Behavior, actions and Sense, sensory information by tran ...

is first detected between the fifth and sixth week of gestation. It is considered primitive neural activity rather than the beginning of conscious thought. Synapses begin forming at 17 weeks, and begin to multiply quickly at week 28 until 3 to 4 months after birth. Although the fetus begins to move during the first trimester, it is not until the second trimester that movement, known as
quickening In pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sex ...
, 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, most women begin to wear maternity clothes. 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 Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe."... modern science is ...
changes, which are entirely normal, including
behavioral Behavior (American English) or behaviour (British English; American and British English spelling differences#-our, -or, see spelling differences) is the Action (philosophy), actions and mannerisms made by individuals, organisms, systems or Arti ...
,
cardiovascular The circulatory system, also called the cardiovascular system or the vascular system, is an organ system An organ system is a group of organs An organ is a group of tissues with similar functions. Plant life and animal life rely on many o ...
, hematologic,
metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life Life is a characteristic that distinguishes physical entities that have biological processes, such as Cell signaling, signaling and self-sustaining ...
,
renal The kidneys are two reddish-brown bean-shaped organs found in vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological ...
, and
respiratory The respiratory system (also respiratory apparatus, ventilatory system) is a biological system A biological system is a complex biological network, network which connects several biologically relevant entities. Biological organization spans sever ...
changes. Increases in
blood sugar The blood sugar level, blood sugar concentration, or blood glucose level is the concentration of glucose present in the blood of humans and other animals. Glucose is a simple sugar, and approximately 4 g of glucose are present in the blood of a 70 ...
,
breathing Breathing (or ventilation) is the process of moving out and in the s to facilitate with the , mostly to flush out and bring in . All aerobic creatures need oxygen for , which uses the oxygen to break down foods for energy and produces ca ...
, and
cardiac output Cardiac output (CO), also known as heart output denoted by the symbols Q, or \dot Q_ , is a term used in cardiac physiologyCardiac physiology or heart function is the study of healthy, unimpaired function of the heart: involving blood flow; Ca ...
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 major ...

and
estrogen Estrogens or oestrogens, are a class of natural or synthetic s responsible for the development and regulation of the female and s. There are three major estrogens that have estrogenic hormonal activity: (E1), (E2), and (E3). Estradiol, an ...

s rise continually throughout pregnancy, suppressing the and therefore also the
menstrual cycle The menstrual cycle is a series of natural changes in hormone A hormone (from the Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country l ...

. A full-term pregnancy at an early age reduces the risk of
breast The breast is one of two prominences located on the upper region of the of s. In females, it serves as the , which produces and secretes milk to feed s. Both females and males develop breasts from the same tissues. At , s, in conjunction ...

,
ovarian The ovary is an organ found 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 bo ...
and
endometrial cancer Endometrial cancer is a cancer that arises from the endometrium (the epithelium, lining of the uterus or womb). It is the result of the abnormal growth of cells (biology), cells that have the ability to invade or spread to other parts of the bod ...
and the risk declines further with each additional full-term pregnancy. The fetus is
genetically Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) Though heredity had been observed for millennia, Gregor Mendel, Moravia, Moravian scientist and Augustinia ...

different from its mother, and can be viewed as an unusually successful
allograft Allotransplant (''allo-'' meaning "other" in Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population ...
. 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 The immune system is a network of biological processes that protects an organism In biology, an organism (from Ancient ...
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 Volume is the quantity of three-dimensional space enclosed by a closed surface, for example, the space that a substance ( solid, liquid, gas, or plasma) or sha ...
increases by 40%. The womb will grow to the size of a lemon by eight weeks. Many symptoms and discomforts of pregnancy 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, are sporadic uterine contractions that may start around six weeks into a pregnancy. However, they are usually felt in the second The second (symbol: s, abbreviation: sec) is t ...
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) is a protruding, flat, or hollowed area on the abdomen The abdomen (colloquially called the belly, tummy, midriff or stomach) is the part of the body between th ...

will sometimes become convex, "popping" out, due to the expanding
abdomen The abdomen (colloquially called the belly, tummy, midriff 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 Trunk (anatomy) ...

. Head engagement, 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 Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing through the v ...

. 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 The venae cavae (; from the Latin for "hollow veins", singular "vena cava" ) are two large veins (venous trunks) that return deoxygenated blood from the body into the heart. In humans there are the superior vena cava and the inferior vena cav ...
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 Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical or dental ...

. 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 Human bonding, social bonding, reproduction, childbirth, and the Postpartum period, pe ...

, a hormone also released during
breastfeeding Breastfeeding, also called nursing, is the process of feeding a mother's breast milk to her infant, either directly from the breast or by expressing (pumping out) the milk from the breast and bottle-feeding it to the infant. The (WHO) reco ...

. 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 United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unit ...
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 222x222px, Eight-month-old sororal twin sisters An infant (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is the more formal or specialised synonym for the common term ''baby'', meaning the very young offspri ...
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 or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing through the vagina or by Caesarean section. In 2015, there were about 135 million births globally. About 15 million ...

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 Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause ...
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 Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical or dental s ...
or
labor induction Labor induction is the process or treatment that stimulates childbirth Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing through the vagina or by Caesarean section. ...
, 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 Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sen ...

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 immediately after childbirth Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing through the vagina or by Caesarean secti ...
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 woman is pregnant Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspri ...

s. However, an important condition with serious health implications that is quite common is the denial of pregnancy by the pregnant woman. About one 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 .

## 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 an ...

* implantation bleeding that occurs at
implantation Implantation may refer to: * Implantation (human embryo), in which the human embryo adheres to the wall of the uterus * Implant (medicine), insertion of implants * Endometrial transplantation, as part of the Endometriosis, theory of retrograde mens ...
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 Thermoregulation is the ability of an organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous s ...
sustained for over 2 weeks after
ovulation Ovulation is the release of egg An egg is the organic vessel containing the in which an develops until it can survive on its own, at which point the animal hatches. An egg results from of an . Most s, (excluding s), and lay eggs, alth ...

*
Chadwick's signChadwick sign is a bluish discoloration of the cervix, vagina, and labium (genitalia), labia resulting from increased blood flow. It can be observed as early as 6 to 8 weeks after Conception (biology), conception, and its presence is an early sign of ...
(darkening of the
cervix The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus The uterus (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. L ...

,
vagina In mammal Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class Mammalia (), and characterized by the presence of mammary glands which in Female#Mammalian female, femal ...

, and
vulva The vulva (plural: vulvas or vulvae; derived from Latin for wrapper or covering) consists of the external . The vulva includes the (or mons veneris), , , , , , , the , , and and vestibular s. The urinary meatus is also included as it opens ...

) *
Goodell's signIn medicine, Goodell sign is an indication of pregnancy. It is a significant softening of the vaginal portion of the cervix from increased vascularization. This vascularization is a result of hypertrophy and engorgement of the vessels below the growi ...
(softening of the vaginal portion of the cervix) *
Hegar's signHegar'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
uterus The uterus (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

isthmus An isthmus ( or ; plural: isthmuses or isthmi; from grc, ἰσθμός, isthmós, neck) is a narrow piece of land connecting two larger areas across an expanse of water by which they are otherwise separated. A tombolo is an isthmus that consist ...

) * Pigmentation 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 alon ...

, (darkening of the skin in a midline of the
abdomen The abdomen (colloquially called the belly, tummy, midriff 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 Trunk (anatomy) ...

, caused by
hyperpigmentation Hyperpigmentation is the darkening of an area of skin or nail (anatomy), nails caused by increased melanin. Causes Hyperpigmentation can be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris.James ...
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 woman is pregnant Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspri ...

s, which detect hormones generated by the newly formed
placenta The placenta is a temporary fetal that begins developing from the shortly after . It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important pro ...

, serving as
biomarkers A biomarker, or biological marker is a measurable wikt:indicator, indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, pathogenic pr ...
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 test A pregnancy test is used to determine whether a woman is pregnant Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspri ...

s are
urine Urine is a liquid by-product A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and ...

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 major ...

levels can also help determine how likely a fetus will survive in those with a threatened miscarriage (bleeding in early pregnancy).

## Ultrasound

Obstetric ultrasonography ultrasonography, or prenatal ultrasound, is the use of in , in which sound waves are used to create real-time visual images of the developing or in the (womb). The procedure is a standard part of care in many countries, as it can provide a v ...
can detect fetal abnormalities, detect multiple pregnancies, and improve gestational dating at 24 weeks. The resultant estimated
gestational age Gestational age is a measure of the age of a pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, such as w ...
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 A genetic disorder is a health problem caused by one or more abnormalities in the genome In the fields of molecular biology and genetics Gen ...
.

# Management

## Prenatal care

Pre-conception counseling Pre-conception counseling (also called pre-conceptual counseling) is a meeting with a health-care professional (generally a physician or midwife) by a woman ''before'' attempting to become pregnant. It generally includes a pre-conception risk asse ...
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 The uterus (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally ...

, weight and fetal heart rate, checking for symptoms of labor, and guidance for what to expect next.

## Nutrition

Nutrition Nutrition is the biochemical Biochemistry or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: st ...
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 Diabetes mellitus (DM), commonly known as diabetes, is a group of metabolic disorders characterized by a high blood sugar level over a prolonged period of time. Symptoms of ...
, 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 and s ...

(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 in which there is incomplete closing of the and the around the during . There are three main types: spina bifida occulta, meningocele and myelomeningocele. Meningocele and myelomeningocele may ...
. 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 Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, convert light energy into chemical energy that, through cellular respiration, can ...

s, and
citrus ''Citrus'' is a of trees and s in the family, . Plants in the genus produce citrus fruits, including important crops such as , , s, s, and . The genus ''Citrus'' is native to , , , , and . Various citrus species have been used and domesticat ...

. In the United States and Canada, most wheat products (flour, noodles) are fortified with folic acid. is a major structural fatty acid in the brain and retina, and is naturally found in breast milk. It is important for the woman to consume adequate amounts of DHA during pregnancy and while nursing to support her well-being and the health of her infant. Developing infants cannot produce DHA efficiently, and must receive this vital nutrient from the woman through the placenta during pregnancy and in breast milk after birth. Several
micronutrients Micronutrients are nutrient, essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for examp ...
are important for the health of the developing fetus, especially in areas of the world where insufficient nutrition is common. Women living in low and middle income countries are suggested to take multiple micronutrient supplements containing iron and folic acid. These supplements have been shown to improve birth outcomes in developing countries, but do not have an effect on perinatal mortality. Adequate intake of folic acid, and iron is often recommended. In developed areas, such as Western Europe and the United States, certain nutrients such as
Vitamin D Vitamin D is a group of fat-soluble secosteroid 250px, The parent steroid skeleton. The B-ring of the parent steroid is broken between C9 and C10 to yield D vitamins. A secosteroid () is a type of steroid , a steroid with 27 carbon atoms ...
and
calcium Calcium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical elem ...

, required for bone development, may also require supplementation. Vitamin E supplementation has not been shown to improve birth outcomes. In a Cochrane review updated in 2021 there was insufficient evidence to support zinc supplementation to improve maternal or
neonatal 222x222px, Eight-month-old sororal twin sisters An infant (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is the more formal or specialised synonym for the common term ''baby'', meaning the very young offspri ...

outcomes. Daily iron supplementation reduces the risk of maternal anemia. Studies of routine daily iron supplementation for pregnant women found improvement in blood iron levels, without a clear clinical benefit. The nutritional needs for women carrying twins or triplets are higher than those of women carrying one baby. Women are counseled to avoid certain foods, because of the possibility of contamination with bacteria or parasites that can cause illness. Careful washing of fruits and raw vegetables may remove these pathogens, as may thoroughly cooking leftovers, meat, or processed meat. Unpasteurized dairy and deli meats may contain ''
Listeria ''Listeria'' is a genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may also refer to ...

,'' which can cause neonatal meningitis, stillbirth and miscarriage. Pregnant women are also more prone to ''
Salmonella ''Salmonella'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruse ...
'' infections, can be in eggs and poultry, which should be thoroughly cooked. Cat feces and undercooked meats may contain the parasite
Toxoplasma gondii ''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan Protozoa (singular protozoon or protozoan, plural protozoa or protozoans) is an informal term for a group of single-celled eukaryote Eukaryotes () are organisms w ...

and can cause
toxoplasmosis Toxoplasmosis is a parasitic disease caused by ''Toxoplasma gondii'', an apicomplexan. Infections with toxoplasmosis usually cause no obvious symptoms in adults. Occasionally, people may have a few weeks or months of mild, flu-like illness such as ...
. Practicing good hygiene in the kitchen can reduce these risks. Women are also counseled to eat seafood in moderation and to eliminate seafood known to be high in mercury because of the risk of birth defects. Pregnant women are counseled to consume caffeine in moderation, because large amounts of caffeine are associated with miscarriage. However, the relationship between caffeine, birthweight, and preterm birth is unclear.

## 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 A nonprofit organization (NPO), also known as a non-business entity, not-for-profit organization, or nonprofit inst ...
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 Mass is the quantity Quantity is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of " ...

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 Adipose tissue, body fat, or simply fat is a loose connective tissue Connective tissue is one of the four basic types of animal tissue (biology), tissue, along with epithelial tissue, muscle ...

(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 A disease is a particular abnormal condition that negatively affects the structure or function (biology), function of all or part of an organism, and that is not due to any immediate external injury. ...
(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 Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical or dental ...
,
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 hyper ...
,
pre-eclampsia Pre-eclampsia is a disorder of pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. P ...
,
macrosomia Large for gestational age (LGA) describes full-term or post-term infants that are born of high birth weight. The term LGA or large for gestational age is defined by birth weight above the 90th percentile for their gestational age and gender. In in ...
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 symphysis, pubic bone. Signs include retraction of the baby's head back into the vagina, known as "turtle sign". Compl ...
. Excessive weight gain can make losing weight after the pregnancy difficult. Some of these complications are risk factors for
stroke A stroke is a medical condition A disease is a particular abnormal condition that negatively affects the structure or function (biology), function of all or part of an organism, and that is not due to any immediate external injury. Dis ...

. 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 all organisms including plants during the entire life span. A sub discipline in Medical Genetics Medical genetics is the branch of medicine that involves the diagnosis and ...
. In the U.S., drugs were classified into categories A, B, C, D and X based on the
Food and Drug Administration The Food and Drug Administration (FDA or USFDA) is a of the . The FDA is responsible for protecting and promoting through the control and supervision of , products, s, and s (medications), s, s, s, s, emitting devices (ERED), cosmetics ...
(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 of l ...

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 happiness, enjoyment, amusement, o ...

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 diso ...
s. *
Alcoholic drinks An alcoholic drink is a drink A drink (or beverage) is a liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, o ...
consumed during pregnancy can cause one or more
fetal alcohol spectrum disorder Fetal alcohol spectrum disorders (FASDs) are a group of conditions that can occur in a person whose mother drank alcohol during pregnancy. Symptoms can include an abnormal appearance, short height, low body weight, small head size, poor coordi ...
s. According to the
CDC CDC may refer to: Organizations Government * Centers for Disease Control and Prevention The United States The United States of America (USA), commonly known as the United States (U.S. or US), or America, is a country Contiguous Unite ...
, 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 In mam ...
,
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 hemorrhagic ...
and
placenta previa Placenta praevia is when the placenta attaches inside the uterus but in an abnormal position near or over the cervical opening. Symptoms include antepartum bleeding, vaginal bleeding in the second half of pregnancy. The bleeding is bright red and t ...

.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 is associated with
premature birth Preterm birth, also known as premature birth, is the birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause ...
,
birth defect A birth defect, also known as a congenital disorder, is a condition present at birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiat ...
s and
attention deficit disorder Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, or excessive activity and impulsivity, which are otherwise not appropriate for a person's age. Some individuals with ADHD also d ...
. * Prenatal methamphetamine exposure can cause
premature birth Preterm birth, also known as premature birth, is the birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause ...

and
congenital abnormalities A birth defect, also known as a congenital disorder, is a condition present at childbirth, birth regardless of its cause. Birth defects may result in disability, disabilities that may be physical disability, physical, intellectual disability, int ...
. 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 (CNS) that is mainly used as a and less commonly as a for and . Methamphetamine was discovered in 1893 and exists as two s: and dextro-methamphetamine. ''Methamphetamine'' properly refer ...

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 The American College of Obstetricians and Gynec ...
has been shown to be
teratogenic Teratology is the study of abnormalities of physiological development in all organisms including plants during the entire life span. A sub discipline in Medical Genetics Medical genetics is the branch of medicine that involves the diagnosis and ...
in large doses in animals, but has not shown any teratogenic effects in humans.

## Exposure to toxins

Intrauterine exposure to
environmental toxins in pregnancy A biophysical environment is a biotic and abiotic surrounding of an organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embodies the Life#Biology, ...
has the potential to cause adverse effects on
prenatal development Prenatal development () includes the development of the embryo and of the foetus during a viviparous animal's gestation. Prenatal development starts with fertilization , in the germinal stage of embryonic development, and continues in fetal d ...

, and to cause
pregnancy complications Complications of pregnancy are health problems that are related to pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than on ...
. 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 Metal toxicity or metal poisoning is the toxic effect of certain metals in certain forms and doses on life. Some metals are toxic when they form poisonous solubl ...
. To minimize exposure to environmental toxins, the ''American College of Nurse-Midwives'' recommends: checking whether the home has lead paint, washing all fresh
fruit In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the ...

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, ...

organic Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ (anatomy), organ Chemistry * Organic matter, matter that has come from a once-living organism, is capable of decay or ...

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 N95 filtering facepiece
respirator A respirator is a device designed to protect the wearer from inhaling hazardous atmospheres, including fumes, vapours, gases Gas is one of the four fundamental states of matter (the others being solid Solid is one of the four ...
s are similar for pregnant women as for non-pregnant women, and wearing a respirator for one hour does not affect the fetal heart rate.

## Sexual activity

Most women can continue to engage in sexual activity, including
sexual intercourse Sexual intercourse (or coitus or copulation) is a sexual activity Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality Human sexuality is the way ...

, throughout pregnancy. Most research suggests that during pregnancy both sexual desire and frequency of sexual relations decrease. In context of this overall decrease in desire, some studies indicate a second-trimester increase, preceding a decrease during the third trimester. 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. Pregnancy alters the
vaginal flora Lactobacilli and a vaginal squamous cell. Vaginal flora, vaginal microbiota or vaginal microbiome are the microorganisms A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós' ...
with a reduction in microscopic species/genus diversity.

## Exercise

Regular
aerobic exercise Aerobic exercise (also known as endurance activities, cardio or cardio-respiratory exercise) is physical exercise Exercise is any bodily activity that enhances or maintains physical fitness Physical fitness is a state of health Health ...

during pregnancy appears to improve (or maintain) physical fitness.
Physical exercise Exercise is any bodily activity that enhances or maintains physical fitness Physical fitness is a state of health Health is a state of physical, mental and social well-being Well-being, also known as ''wellness'', ''prudential valu ...
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 a baby is delivered through an incision in the pregnant person's abdomen, often performed because vaginal delivery would put the baby or preg ...
, 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 known as dyspnea (BrE British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, and standard) is a language variety that has undergone substantial codificat ...
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 Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response in ...
).

## 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 tim ...
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 major ...

and
estrogen Estrogens or oestrogens, are a class of natural or synthetic s responsible for the development and regulation of the female and s. There are three major estrogens that have estrogenic hormonal activity: (E1), (E2), and (E3). Estradiol, an ...

during pregnancy make
gingivitis Gingivitis is a non-destructive disease that causes inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, o ...

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 lining ...
become edematous, red in colour, and tend to bleed. Also a
pyogenic granuloma 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 Irritation, in biology Biology is the natural science that studies life ...
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 A disease is a particular abnormal condition that negatively affects the structure A structure is an arrangement and organization of interrelated elements in ...
measures. There have been suggestions that severe
periodontitis Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the Periodontium, tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen, red, and may bleed. It is considered the ...
may increase the risk of having
preterm birth Preterm birth, also known as premature birth, is the birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause ...
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 intensive ...
; 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 Periodontium, tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen, red, and may bleed. It is considered the ...

## 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, specially at over 28 weeks. During flights, the risk of
deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis Venous thrombosis is blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. ...
is decreased by getting up and walking occasionally, as well as by avoiding dehydration.
Full body scanner 300px, Image from an active millimeter wave 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. Depending ...
s do not use ionizing radiation, and are safe in pregnancy. Airports can also possibly use backscatter X-ray scanners, which use a very low dose, but where safety in pregnancy is not fully established.

# 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, also known as a hemorrhage, haemorrhage, or simply blood loss, is blood Blood is a body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substan ...
(72,000),
infections An infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host A host is a person responsible for guests at an event or for providing hospitality during it. Host may ...
(20,000), hypertensive diseases of pregnancy (32,000),
obstructed labor Obstructed labour, also known as labour dystocia, is when the baby does not exit the pelvis during childbirth Childbirth, also known as labour or delivery, is the ending of pregnancy where one or more babies leaves the uterus by passing thro ...
(10,000), and
pregnancy with abortive outcome Pregnancy, also known as gestation, is the time during which one or more offspring In biology, offspring are the young born of living organism, organisms, produced either by a single organism or, in the case of sexual reproduction, two orga ...
(20,000), which includes
miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the natural loss of an embryo or fetus before it is fetal viability, able to survive independently. Some use the cutoff of 20 weeks of gestation, after whi ...
,
abortion Abortion is the ending of a pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring In biology, offspring are the young born of living organism, organisms, produced either by a single organism ...

, and
ectopic pregnancy Ectopic pregnancy is a complication 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 p ...

. The following are some examples of pregnancy complications: * Pregnancy induced hypertension *
Anemia Anemia ( anaemia) is a decrease in the total amount of s (RBCs) or in the , or a lowered ability of the blood to carry . When anemia comes on slowly, the symptoms are often vague and may include , weakness, , and a poor ability to exercise. W ...

*
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, Fatigue (medical), low energy, anxiety, crying episodes, irrit ...
, a common but solvable complication following childbirth that may result from decreased hormonal levels. *
Postpartum psychosis Early in the history of medicine, it was recognized that severe mental illness sometimes started abruptly in the days after childbirth, later known as puerperal or postpartum psychosis. Gradually, it became clear that this was not a single and un ...
* 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 (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 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 p ...

, including
abdominal pregnancy An abdominal pregnancy can be regarded as a form of an ectopic pregnancy Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus The uterus (from Latin Latin (, or , ) is a classical language bel ...
, 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 In physiology, dehydration is a lack of total body water, with an accompanying disruption of Meta ...
, excessive nausea and vomiting that is more severe than normal morning sickness. *
Pulmonary embolism Pulmonary embolism (PE) is a blockage of an pulmonary artery, 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 dyspnea, shortness of breath, chest pain pa ...

, 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 Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more ...
is a rare complication thought to be brought about by a disruption in the metabolism of fatty acids by
mitochondria A mitochondrion (; ) is a double-membrane Image:Schematic size.jpg, up150px, Schematic of size-based membrane exclusion A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, i ...

. There is also an increased susceptibility and severity of certain infections in pregnancy.

# 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 Diabetes mellitus (DM), commonly known as diabetes, is a group of metabolic disorders characterized by a high blood sugar level over a prolonged period of time. Symptoms often include frequent urination, incr ...
deals with the interactions of
diabetes mellitus Diabetes mellitus, commonly known as just diabetes, is a group of metabolic disorder A metabolic disorder is a disorder that negatively alters the body's processing and distribution of macronutrients such as proteins, fats, and carbohydrates ...
(not restricted to
gestational diabetes Gestational diabetes is a condition in which a woman without diabetes Diabetes mellitus (DM), commonly known as diabetes, is a group of metabolic disorders characterized by a high blood sugar level over a prolonged period of time. Symptoms of ...
) 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 clin ...
(too much
amniotic fluid The amniotic fluid is the protective liquid contained by the amniotic sac The amniotic sac, commonly called the bag of waters, sometimes the membranes, is the sac in which the fetus develops in amniotes. It is a thin but tough transparent pair o ...
), and birth defects. * Thyroid disease in pregnancy 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 or celiac disease 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 barley. Classic symptoms include gastrointe ...
can cause a
miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the natural loss of an embryo or fetus before it is fetal viability, able to survive independently. Some use the cutoff of 20 weeks of gestation, after whi ...
,
intrauterine growth restriction Intrauterine growth restriction (IUGR) refers to poor growth of a fetus while in the mother's womb during pregnancy. The causes can be many, but most often involve poor maternal nutrition or lack of adequate oxygen supply to the fetus. At least ...
,
small for gestational age Small for gestational age (SGA) newborns are those who are smaller in size than normal for the gestational age, most commonly defined as a weight below the 10th percentile for the gestational age. Causes Being small for gestational age is broadly ...
,
low birthweight Birth weight is the body weight Human body weight refers to a person's mass or weight. Body weight is measured in kilogram The kilogram (also kilogramme) is the base unit of mass in the International System of Units (SI), the current metric ...
and
preterm birth Preterm birth, also known as premature birth, is the birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause ...
. 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 (small intestine), absorption of Nutrient, food nutrients across the gastrointestinal tract, gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on ...
, but by the
autoimmune response An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. There are at least 80 types of autoimmune diseases. Nearly any body part can be involved. Common symptoms include low grade fever and fatigue ...
elicited by the exposure to
gluten Gluten is a protein naturally found in some grains including wheat, barley, and rye. Although, strictly speaking, "gluten" pertains only to wheat proteins, in the medical literature it refers to the combination of prolamin and glutelin proteins ...

, which causes damage to the
placenta The placenta is a temporary fetal that begins developing from the shortly after . It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important pro ...

. 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, Khorasan wheat, kamut, and triticale), as well as barley, rye, and oa ...
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 the occurrence of systemic lupus erythematosus Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system The immune system is a network of bio ...
. * Hypercoagulability in pregnancy is the propensity of pregnant women to develop
thrombosis Thrombosis (from Ancient Greek Ancient Greek includes the forms of the used in and the from around 1500 BC to 300 BC. It is often roughly divided into the following periods: (), Dark Ages (), the period (), and the period (). Anc ...

(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 Thrombosis (from Ancient Greek Ancient Greek includes the forms of the Greek la ...
(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 within the first 24 hours following childbirth Childbirth, also known as labour or delivery, is the ending of ...
. However, in combination with an underlying hypercoagulable state, the risk of thrombosis or embolism may become substantial.Page 264 in:

# Medical imaging

Medical imaging Medical imaging is the technique and process of imaging Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image). Imaging technology is the application of materi ...
may be indicated in pregnancy because of
pregnancy complications Complications of pregnancy are health problems that are related to pregnancy Pregnancy, also known as gestation, is the time during which one or more offspring develops inside a woman. A multiple birth, multiple pregnancy involves more than on ...
, 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 Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different academic discipline, disciplines, with variations in the use of logic, analytics, and e ...
including
obstetric ultrasonography ultrasonography, or prenatal ultrasound, is the use of in , in which sound waves are used to create real-time visual images of the developing or in the (womb). The procedure is a standard part of care in many countries, as it can provide a v ...
, and magnetic resonance imaging (MRI) without
contrast agents A contrast agent (or contrast medium) is a substance Substance may refer to: * Substance (Jainism), a term in Jain ontology to denote the base or owner of attributes * Chemical substance, a material with a definite chemical composition * Matter, any ...
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 Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an ob ...
,
CT scan A CT scan or computed tomography scan (formerly known as computed axial tomography or CAT scan) is a medical image, imaging Scientific technique, technique used in radiology to obtain detailed internal images of the body noninvasively for Diagno ...

and nuclear medicine imaging result in some degree of
ionizing radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of s or s that have sufficient to s or s by detaching s from them. The particles generally travel at a speed that is greater than 1% of , and the electromagnetic w ...
exposure, but in most cases the
absorbed dose Absorbed dose is a dose quantity which is the measure of the energy deposited in matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be to ...
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 natural loss of an embryo or fetus before it is fetal viability, able to survive independently. Some use the cutoff of 20 weeks of gestation, after whi ...
,
birth defect A birth defect, also known as a congenital disorder, is a condition present at birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiat ...
s and
intellectual disability Intellectual disability (ID), also known as general learning disability and formerly mental retardation (MR),Rosa's Law Rosa's Law is a United States The United States of America (USA), commonly known as the United States (U.S. or US), or ...
.

# Epidemiology

About 213 million pregnancies occurred in 2012 of which 190 million were in the
developing world Image:Imf-advanced-un-least-developed-2008.svg, 450px, Example of Older Classifications by the International Monetary Fund, IMF and the United Nations, UN from 2008 A developing country is a country with a less developed Industrial sector, i ...
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 Drama is the specific Mode (literature), mode of fiction Mimesis, represented in performance: a Play (theatre), play, opera, mime, ballet, etc., performed in a theatre, or on Radio drama, radio or tele ...
. 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 geographic region In geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of the Earth ...

. 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 (TFR) in 2013 was estimated to be highest in
Niger ) , official_languages = French French (french: français(e), link=no) may refer to: * Something of, from, or related to France France (), officially the French Republic (french: link=no, République française), is a country primar ...

(7.03 children/woman) and lowest in
Singapore Singapore (), officially the Republic of Singapore, is a sovereign state, sovereign island 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, bor ...

(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 Drama is the specific Mode (literature), mode of fiction Mimesis, represented in performance: a Play (theatre), play, opera, mime, ballet, etc., performed in a theatre, or on Radio drama, radio or tele ...
, and between a quarter and half of those unplanned pregnancies were unwanted pregnancies.

# Society and 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 250px, Jamaica_Plain.html"_;"title="Botánicas_such_as_this_one_in_Jamaica_Plain">Botánicas_such_as_this_one_in_Jamaica_Plain,_Boston,_cater_to_the_Hispanic_and_Latino_Americans.html" "title="Jamaica_Plain,_Boston.html" ;"title="Jamaica_Plain.h ...

or religion. The
baby shower "Baby Shower" is the fourth episode of the fifth season of the television series upright=1.35, A live television show set and cameras A television show – or simply TV show – is any content produced for viewing on a television set which ca ...

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 Sociology is a social science Social science is the Branches of science, branch of science devoted to the study of society, societies and the Social relation, relationsh ...
. The prospective child may preliminarily be placed into numerous
social role A role (also rôle or social role) is a set of connected behavior Behavior (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the Eng ...
s. The parents' relationship and the relation between parents and their surroundings are also affected. A belly cast 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 ''lamassu 300px, ''Lamassu'' from Dur-Sharrukin. University of Chicago Oriental Institute. Syrian limestone Neo-Assyrian Period, c ...

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 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 through following the onset of . The is the average number of children born by a female during her lifetime and is quantified . Fertility is addressed when there is a difficulty or an inability to repro ...
. 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 continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as cont ...

and collectively known as
Venus figurines A Venus figurine is any portraying a woman, usually carved in .Fagan, Brian M., Beck, Charlotte, "Venus Figurines", ''The Oxford Companion to Archaeology'', 1996, Oxford University Press, pp. 740–741 Most have been unearthed in , but others ...
. Some of these appear to be pregnant. Due to the important role of the
Mother of God Catholic Mariology is Mariology Mariology is the theological study of Mary, the mother of Jesus Jesus; he, יֵשׁוּעַ, '' Yēšū́aʿ''; ar, عيسى, ʿĪsā ( 4 BC AD 30 / 33), also referred to as Jesus of Nazareth or ...

in
Christianity Christianity is an Abrahamic religions, Abrahamic, Monotheism, monotheistic religion based on the Life of Jesus in the New Testament, life and Teachings of Jesus, teachings of Jesus, Jesus of Nazareth. It is the Major religious groups, world's ...

, the Western visual arts have a long tradition of depictions of pregnancy, especially in the biblical scene of the
Visitation Visitation may refer to: Law * Visitation (law) or contact, the right of a non-custodial parent to visit with their children * Prison visitation rights, the rules and conditions under which prisoners may have visitors Music * Visitation (Division ...
, and devotional images called a ''
Madonna del Parto Madonna Louise Ciccone (; ; born August 16, 1958) is an American singer, songwriter, and actress. Referred to as the " Queen of Pop", she is regarded as one of the most significant figures in popular culture. Madonna is noted for her continua ...
''. The unhappy scene usually called ''Diana and Callisto'', showing the moment of discovery of Callisto'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 Literary realism, Victorian realist in the tradition of George Eliot, he was influenced both in his novels and in his poetry by Romanticism, including the poetry ...

's 1891 novel ''
Tess of the d'Urbervilles ''Tess of the d'Urbervilles: A Pure Woman Faithfully Presented'' is a novel by Thomas Hardy. It initially appeared in a Book censorship, censored and Serialized novel, serialised version, published by the British illustrated newspaper ''The Grap ...
'' and Goethe's 1808 play ''
Faust Faust is the protagonist 200px, Shakespeare's ''Hamlet, Prince of Denmark.'' William Morris Hunt, oil on canvas, c. 1864 A protagonist (from grc, πρωταγωνιστής, translit=prōtagōnistḗs, lit=one who plays the first part, chief ...
''. File:1700 Zick Anatomisches Modell einer schwangeren Frau anagoria.JPG, Anatomical model of a pregnant woman; Stephan Zick (1639–1715); 1700;
Germanisches Nationalmuseum The Germanisches National Museum is a museum in Nuremberg, Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official language , languages = ...
File:Macedonia-02845 (10906093425).jpg, Statue of a pregnant woman,
Macedonia Macedonia most commonly refers to: * North Macedonia North Macedonia, ; sq, Maqedonia e Veriut, (Macedonia until February 2019), officially the Republic of North Macedonia,, is a country in Southeast Europe. It gained independence in ...
File:Merrion Square maid.jpg, Bronze figure of a pregnant naked woman by Danny Osborne,
Merrion Square Merrion Square () is a Georgian architecture, Georgian garden square on the Southside Dublin, southside of Dublin city centre. History The square was laid out in 1752 by the estate of Viscount FitzWilliam and was largely complete by the beginni ...
File:Gheeraerts Susanna Temple, later Lady Lister.jpg,
Marcus Gheeraerts the Younger Marcus Gheeraerts (also written as Gerards or Geerards; 1561/62 – 19 January 1636) was a Flemish , described as "the most important artist of quality to work in England in large-scale between and "Strong 1969, p. 22 He was brought to England as ...
''Portrait of Susanna Temple'', second wife of Sir Martin Lister, 1620 File:Octave TASSAERT The Waif -L'abandonnée.jpg, Octave Tassaert, ''The Waif'' aka ''L'abandonnée'' 1852,
Musée Fabre The Musée Fabre is a museum in the southern France, French city of Montpellier, capital of the Hérault ''departments of France, département''. The museum was founded by François-Xavier Fabre, a Montpellier painter, in 1825. Beginning in 2003, t ...
,
Montpellier Montpellier (, , ; oc, Montpelhièr , it, Mompellieri ) is a city in southern France France (), officially the French Republic (french: link=no, République française), is a List of transcontinental countries, transcontinental coun ...

## Infertility

Modern reproductive medicine offers many forms of
assisted reproductive technology Assisted reproductive technology (ART) includes medical procedures used primarily to address infertility. This subject involves procedures such as in vitro fertilization, intracytoplasmic sperm injection (ICSI), cryopreservation of gametes or embryo ...
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 ovarian follicle, follicle development of the ovary. There are very few fertility medic ...
, artificial insemination, and
surrogacy Surrogacy is an arrangement, often supported by a legal agreement, whereby a woman (the gestational carrier) agrees to bear a child for another person or people, who will become the child's parent(s) after birth. People may seek a surrogacy a ...
.

## Abortion

An abortion is the termination of an embryo or fetus, either naturally or via medical methods. When carried out by choice, it is usually within the first trimester, sometimes in the second, and rarely in the third. Not using contraception, contraceptive failure, poor family planning or rape can lead to undesired pregnancies. Legality of socially indicated abortions varies widely both internationally and through time. In most countries of Western Europe, abortions during the first trimester were a criminal offense a few decades ago but have since been legalized, sometimes subject to mandatory consultations. In Germany, for example, as of 2009 less than 3% of abortions had a medical indication.

## 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 Employment discrimination is a form of discrimination based on race, gender, religion Religion is a social system, social-cultural system of designated religious behaviour, ...
. 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 The United States of America (USA), commonly known as the United States (U.S. or US), or America, is a country Contiguous United States, primarily located i ...
. In 2014, the American state of
Tennessee Tennessee (, ), officially the State of Tennessee, is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The S ...

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 state, sovereign island 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, bor ...

, the ''Employment of Foreign Manpower Act'' forbids current and former
work permit A work permit or work visa is the permission to take a job A job, employment, work or occupation, is a person A person (plural people or persons) is a being that has certain capacities or attributes such as reason, morality, consciousness ...
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.

## Marriage and education

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%.

## 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, SIDS, preterm birth, and low birth weight 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, 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.

* Cryptic pregnancy * Male pregnancy * Transgender pregnancy *
Couvade syndrome Couvade syndrome, also called sympathetic pregnancy, is a proposed condition in which an expectant father or other parent experiences some of the same symptoms and behavior as their wife or birth parent. These most often include major weight gain, a ...
* Simulated pregnancy