A pre-existing disease in pregnancy is a disease that is not directly caused by the

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

, in contrast to various

complications of pregnancy Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal d ...

, but which may become worse or be a potential risk to the pregnancy (such as causing pregnancy complications). A major component of this risk can result from necessary use of drugs in pregnancy to manage the disease. In such circumstances, women who wish to continue with a pregnancy require extra medical care, often from an interdisciplinary team. Such a team might include (besides an obstetrician) a specialist in the disorder and other practitioners (for example, maternal-fetal specialists or obstetric physicians,

dietician A dietitian, medical dietitian, or dietician is an expert in identifying and treating disease-related malnutrition and in conducting medical nutrition therapy, for example designing an enteral tube feeding regimen or mitigating the effects of ...

s, etc.).

Chronic hypertension

Chronic hypertension in pregnancy can lead to increased complications for both the mother and fetus. Maternal complications include superimposed pre-eclampsia and caesarean delivery. Fetal complications include preterm delivery, low birth weight, and death. Increasing rates of obesity and metabolic syndrome play a key role in the increased prevalence of chronic hypertension and associated complications. While high blood pressure treatment has been shown to decrease the incidence of severe hypertension during pregnancy, there was no significant difference in pregnancy complications (for example, superimposed pre-eclampsia, stillbrith/neonatal death, small for gestational age).

Endocrine disorders

Diabetes mellitus

Diabetes mellitus and pregnancy deals with the interactions of

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

(not restricted to

gestational diabetes Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and of ...

) and pregnancy. Risks for the child include miscarriage, growth restriction, growth acceleration, fetal obesity (macrosomia), polyhydramnios and birth defects.

Thyroid disease

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. The most effective way of screening for thyroid dysfunction is not known. A review found that more women were diagnosed with thyroid dysfunction when all pregnant women were tested instead of just testing those at 'high-risk' of thyroid problems (those with family history, signs or symptoms). Finding more women with thyroid dysfunction meant that the women could have treatment and management through their pregnancies. However the outcomes of the pregnancies were surprisingly similar so more research is needed to look at the effects of screening all pregnant women for thyroid problems.

Hypercoagulability

Hypercoagulability in pregnancy Hypercoagulability in pregnancy is the propensity of pregnant women to develop thrombosis (blood clots). Pregnancy itself is a factor of hypercoagulability (pregnancy-induced hypercoagulability), as a physiologically adaptive mechanism to prevent ...

is the propensity of pregnant women to develop

thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thr ...

(blood clots) such as a deep vein thrombosis with a potential subsequent pulmonary embolism. Pregnancy itself is a factor of hypercoagulability (pregnancy-induced hypercoaguability), as a physiologically adaptive mechanism to prevent ''post partum'' bleeding. The pregnancy associated hypercoaguability is attributed to an increased synthesis of coagulation factors, such as fibrinogen, by the liver through the effects of estrogen. When combined with any additional underlying hypercoagulable state, the risk of thrombosis or embolism may become substantial.Page 264 in: Multiple pre-existing genetic disorders can worsen the hypercoaguable state observed in pregnancy. Examples include: *

Factor V Leiden Factor V Leiden (rs6025 or ''F5'' p.R506Q) is a variant (mutated form) of human factor V (one of several substances that helps blood clot), which causes an increase in blood clotting (hypercoagulability). Due to this mutation, protein C, an anticoa ...

* Prothrombin G20210A * Protein C deficiency * Protein S deficiency * Antithrombin III deficiency

Infections

Vertically transmitted infections

Many

infectious diseases An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

have a risk of

vertical transmission Vertical transmission of symbionts is the transfer of a microbial symbiont from the parent directly to the offspring. Many metazoan species carry symbiotic bacteria which play a mutualistic, commensal, or parasitic role. A symbiont is acquire ...

to the fetus, known as TORCH infections. Examples based on the TORCHES acronym include: *

Toxoplasma ''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but felids, such as d ...

* Other: Parvovirus B19, Zika,

Chickenpox Chickenpox, also known as varicella, is a highly contagious disease caused by the initial infection with varicella zoster virus (VZV). The disease results in a characteristic skin rash that forms small, itchy blisters, which eventually scab ...

Rubella Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus. This disease is often mild, with half of people not realizing that they are infected. A rash may start around two weeks after exposure and ...

Cytomegalovirus ''Cytomegalovirus'' (''CMV'') (from ''cyto-'' 'cell' via Greek - 'container' + 'big, megalo-' + -''virus'' via Latin 'poison') is a genus of viruses in the order '' Herpesvirales'', in the family '' Herpesviridae'', in the subfamily '' Beta ...

* Herpes simplex or Neonatal herpes simplex * HIV * Syphilis Infections in pregnancy also raise particular concerns about whether or not to use drugs in pregnancy (that is,

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

s or

antiviral Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do ...

s) to treat them. For example, pregnant women who contract H1N1 influenza infection are recommended to receive antiviral therapy with either

oseltamivir Oseltamivir, sold under the brand name Tamiflu, is an antiviral medication used to treat and prevent influenza A and influenza B, viruses that cause the flu. Many medical organizations recommend it in people who have complications or are at hig ...

(which is the preferred medication) or zanamivir.Health Care Guideline: Routine Prenatal Care. Fourteenth Edition.
By the Institute for Clinical Systems Improvement. July 2010. Both

amantadine Amantadine, sold under the brand name Gocovri among others, is a medication used to treat dyskinesia associated with parkinsonism and influenza caused by type A influenzavirus, though its use for the latter is no longer recommended due to wi ...

and rimantadine have been found to be

teratogenic Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related ...

and embryotoxic when given at high doses in animal studies.

Candidal vulvovaginitis

In pregnancy, changes in the levels of female sex hormones, such as

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

, make a woman more likely to develop

candidal vulvovaginitis Vaginal yeast infection, also known as candidal vulvovaginitis and vaginal thrush, is excessive growth of yeast in the vagina that results in irritation. The most common symptom is vaginal itching, which may be severe. Other symptoms include burn ...

. During pregnancy, the ''Candida'' fungus is more prevalent (common), and recurrent infection is also more likely. There is no clear evidence that treatment of asymptomatic candidal vulvovaginitis in pregnancy reduces the risk of preterm birth. Candidal vulvovaginitis in pregnancy should be treated with intravaginal

clotrimazole Clotrimazole, sold under the brand name Lotrimin, among others, is an antifungal medication. It is used to treat vaginal yeast infections, oral thrush, diaper rash, tinea versicolor, and types of ringworm including athlete's foot and jock it ...

or nystatin for at least 7 days.

Bacterial vaginosis

Bacterial vaginosis Bacterial vaginosis (BV) is a disease of the vagina caused by excessive growth of bacteria. Common symptoms include increased vaginal discharge that often smells like fish. The discharge is usually white or gray in color. Burning with urination ...

is an imbalance of naturally occurring bacterial flora in the vagina. Bacterial vaginosis occurring during pregnancy may increase the risk of

pregnancy complications Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal d ...

, most notably

premature birth Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is between 2 ...

miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical lo ...

. However, this risk is small overall and appears more significant in women who have had such complications in an earlier pregnancy.

Valvular heart disease

In case of valvular heart disease in pregnancy, the maternal physiological changes in pregnancy confer additional load on the heart and may lead to complications. In individuals who require an artificial heart valve, consideration must be made for deterioration of the valve over time (for bioprosthetic valves) versus the risks of blood clotting in pregnancy with mechanical valves with the resultant need of drugs in pregnancy in the form of

anticoagulant Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where they ...

Other autoimmune disorders

Celiac disease

Untreated

celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...

can cause spontaneous abortion (miscarriage),

intrauterine growth restriction Intrauterine growth restriction (IUGR), or fetal growth restriction, refers to poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's ...

small for gestational age 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 and preterm birth. 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, but by the autoimmune response elicited by the exposure to

gluten Gluten is a structural protein naturally found in certain cereal grains. Although "gluten" often only refers to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grai ...

, which causes damage to the

placenta The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mat ...

. The

gluten-free diet A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats. The inclu ...

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.

Systemic lupus erythematosus

Systemic lupus erythematosus and pregnancy confers an increased rate of fetal death ''in utero'' and spontaneous abortion (miscarriage), as well as of

neonatal lupus Neonatal lupus erythematosus is an autoimmune disease in an infant born to a mother with anti-Ro/SSA and with or without anti-La/SSB antibodies. The disease most commonly presents with a rash resembling subacute cutaneous lupus erythematosus and c ...

Behçet's disease

Pregnancy does not have an adverse effect on the course of Behçet's disease and may possibly ameliorate its course. Still, there is a substantial variability in clinical course between patients and even for different pregnancies in the same patient. Also, the other way around, Behçet's disease confers an increased risk of

and Cesarean section.

Multiple sclerosis

Being pregnant decreases the risk of relapse in

multiple sclerosis Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. Thi ...

; however, during the first months after delivery the risk increases. Overall, pregnancy does not seem to influence long-term disability. Multiple sclerosis does not increase the risk of

congenital abnormality A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...

.Multiple Sclerosis: Pregnancy Q&A
from Cleveland Clinic, retrieved January 2014.

Mental health

Depression in pregnancy

The effects of depression during pregnancy are difficult to parse from depression before pregnancy as the symptoms of the two overlap. However, the biggest risk factor of depression during pregnancy is a prior history of depression. Most of the research is focused on the consequences of untreated depression regardless if the depression developed during pregnancy or if it was there before conception. Untreated depression has been linked to premature birth, low birth weight, fetal growth restriction, and postnatal complications. On the other hand, however, anti-depressant medications also come with a small risk of pre-term birth, low birth weight, and persistent pulmonary hypertension.

Respiratory disease

Asthma

In the United States, the prevalence of asthma among pregnant women is between 8.4% and 8.8%. Asthma in pregnant women is strongly associated with multiple adverse health outcomes, including pre-eclampsia, preterm birth, and low birth weight. Other conditions such as gestational diabetes, placenta previa, and hemorrhage are inconsistently correlated to asthma. Poorly controlled and severe asthma may exacerbate conditions associated with maternal and neonate morbidity and mortality. Asthma treatment recommendations during pregnancy are similar to those in non-pregnant women.

Structural (congenital) abnormalities of the uterus

Structural abnormalities of the uterus include conditions like septate uterus, bicornuate uterus, arcuate uterus, and didelphys uterus. Most of these abnormalities occur when the Müllerian ducts are fused improperly or incompletely. Women with these congenital abnormalities are usually unaware as these conditions do not usually do not present any symptoms. During pregnancy, these conditions are associated with infertility, preterm birth, fetal malpresentation, and early miscarriages. Among these uterine abnormalities, those with canalization defects, i.e., not having a normal uterine canal such as septate defects have the worse pregnancy outcomes. Surgical treatment is only recommended for individuals who have had recurrent miscarriages and have a septate uterus; however, the risks of surgery, especially scarring of the womb should be considered. Further evidence from randomized controlled trials are required to establish conclusively whether surgery is the better option when its risks and rewards are compared with the risks of the adverse pregnancy outcomes.

Others

The following conditions may also become worse or be a potential risk to the pregnancy: *

Cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bl ...

* Chronic hypertension *

Cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...

* Congenital disorders that may be passed on to offspring * Heart defects, especially primary pulmonary hypertension and Eisenmenger's syndrome * Kidney disorders *

Mental health Mental health encompasses emotional, psychological, and social well-being, influencing cognition, perception, and behavior. It likewise determines how an individual handles stress, interpersonal relationships, and decision-making. Mental healt ...

. ** Depression has been linked to higher rates of preterm delivery. * Respiratory disorders and diseases (associated, for example, with

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 dangerou ...

) **

Asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, ...

Seizure disorders Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...

* Structural abnormalities in the

cervix The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...

* Structural abnormalities in the

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. Th ...

Viral hepatitis Viral hepatitis is liver inflammation due to a viral infection. It may present in acute form as a recent infection with relatively rapid onset, or in chronic form. The most common causes of viral hepatitis are the five unrelated hepatotropic v ...

References

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