A pre-existing disease in pregnancy is a disease that is not directly caused by the
pregnancy, in contrast to various
complications of pregnancy, 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,
dieticians, etc.).[MMHE 1]
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.[1] Women who have chronic hypertension before their pregnancy are at increased risk of complications such as
premature birth,
low birthweight or
stillbirth.[2] Women who have high blood pressure and had complications in their pregnancy have three times the risk of developing
cardiovascular disease compared to women with normal blood pressure who had no complications in pregnancy. Monitoring pregnant women's blood pressure can help prevent both complications and future cardiovascular diseases.[3][4] 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).[5]
Diabetes mellitus and pregnancy deals with the interactions of
diabetes mellitus (not restricted to
gestational diabetes) and pregnancy. Risks for the child include miscarriage, growth restriction, growth acceleration, fetal obesity (macrosomia), polyhydramnios 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. The most effective way of screening for thyroid dysfunction is not known.[6] 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).[6] 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.[6]
Hypercoagulability in pregnancy is the propensity of pregnant women to develop
thrombosis (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.[7] 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.[7] Multiple pre-existing genetic disorders can worsen the hypercoaguable state observed in pregnancy. Examples include:
In pregnancy, changes in the levels of female sex hormones, such as
estrogen, make a woman more likely to develop
candidal vulvovaginitis. During pregnancy, the Candida fungus is more prevalent (common), and recurrent infection is also more likely.[12] There is no clear evidence that treatment of asymptomatic candidal vulvovaginitis in pregnancy reduces the risk of
preterm birth.[13] Candidal vulvovaginitis in pregnancy should be treated with intravaginal
clotrimazole or
nystatin for at least 7 days.[14]
Bacterial vaginosis
Bacterial vaginosis is an imbalance of naturally occurring
bacterial flora in the vagina. Bacterial vaginosis occurring during pregnancy may increase the risk of
pregnancy complications, most notably
premature birth or
miscarriage.[15] However, this risk is small overall and appears more significant in women who have had such complications in an earlier pregnancy.[16]
Untreated
celiac disease can cause
spontaneous abortion (miscarriage),
intrauterine growth restriction,
small for gestational age,
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, which causes damage to the
placenta. The
gluten-free diet avoids or reduces the risk of developing reproductive disorders in pregnant women with celiac disease.[17][18] Also, pregnancy can be a trigger for the development of celiac disease in genetically susceptible women who are consuming gluten.[19]
Pregnancy does not have an adverse effect on the course of
Behçet's disease and may possibly ameliorate its course.[20][21] Still, there is a substantial variability in clinical course between patients and even for different pregnancies in the same patient.[20] Also, the other way around, Behçet's disease confers an increased risk of
pregnancy complications,
miscarriage and
Cesarean section.[21]
Multiple sclerosis
Being pregnant decreases the risk of relapse in
multiple sclerosis; however, during the first months after delivery the risk increases.[22] Overall, pregnancy does not seem to influence long-term disability.[22] Multiple sclerosis does not increase the risk of
congenital abnormality or
miscarriage.[23][24]
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.[25] 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.[25] 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.[26][25]
Respiratory disease
Asthma
In the United States, the
prevalence of asthma among pregnant women is between 8.4% and 8.8%.[27] Asthma in pregnant women is strongly associated with multiple adverse health outcomes, including pre-eclampsia, preterm birth, and low birth weight.[28][29] Other conditions such as gestational diabetes, placenta previa, and hemorrhage are inconsistently correlated to asthma.[30] Additionally, women with Asthma face a higher likelihood of complications during labor and delivery, such as breech presentation and caesarean delivery.[31] Poorly controlled and severe asthma may exacerbate conditions associated with maternal and neonate morbidity and mortality.[30][32] Asthma treatment recommendations during pregnancy are similar to those in non-pregnant women.[33]
As of 2018, Asthma was the most prevalent respiratory disorder to complicate pregnancy, remaining a high-risk condition despite therapeutic advancements.[34] Preventing asthma exacerbations during pregnancy is crucial to reduce the risk of complications and poor outcomes.[31]
The course of asthma during pregnancy
The course of asthma during pregnancy can vary, with some patients experiencing worsening symptoms while others see improvement.
As of 2006, it was believed the course of asthma during pregnancy varied with a similar proportion of women improving, remaining stable, or worsening.[35] However, as of 2013, it was found that deterioration may manifest in approximately 20% of women, improvement in around 30%, and no significant change observed in the remaining 50%.[36]
Structural (congenital) abnormalities of the uterus
Structural abnormalities of the uterus include conditions like septate uterus, bicornuate uterus, arcuate uterus, and didelphys uterus.[37] 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.[37] 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.[37]
Others
The following conditions may also become worse or be a potential risk to the pregnancy:
^
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abUzun, S.; Alpsoy, E.; Durdu, M.; Akman, A. (2003). "The clinical course of Behçet's disease in pregnancy: A retrospective analysis and review of the literature". The Journal of Dermatology. 30 (7): 499–502.
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^Getahun, D; Ananth, CV; Peltier, MR; Smulian, JC; Vintzileos, AM (2006). "Acute and chronic respiratory diseases in pregnancy: associations with placental abruption". American Journal of Obstetrics and Gynecology. 195 (4): 1180–4.
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10.1016/j.ajog.2006.07.027.
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^Merck.
"Cancer during pregnancy". Merck Manual Home Health Handbook. Merck Sharp & Dohme. Archived from
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