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
[edit]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]
Endocrine disorders
[edit]Diabetes mellitus
[edit]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
[edit]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
[edit]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:
- Factor V Leiden
- Prothrombin G20210A
- Protein C deficiency
- Protein S deficiency
- Antithrombin III deficiency
Infections
[edit]Vertically transmitted infections
[edit]Many infectious diseases have a risk of vertical transmission to the fetus, known as TORCH infections. Examples based on the TORCHES acronym include:
- Toxoplasma
- Other: Parvovirus B19, Zika, Chickenpox
- Rubella
- Cytomegalovirus
- Herpes simplex or Neonatal herpes simplex
- HIV[8][9]
- Syphilis[10]
Infections in pregnancy also raise particular concerns about whether or not to use drugs in pregnancy (that is, antibiotics or antivirals) to treat them. For example, pregnant women who contract H1N1 influenza infection are recommended to receive antiviral therapy with either oseltamivir (which is the preferred medication) or zanamivir.[11] Both amantadine and rimantadine have been found to be teratogenic and embryotoxic when given at high doses in animal studies.[11]
Candidal vulvovaginitis
[edit]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
[edit]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]
Valvular heart disease
[edit]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 anticoagulants.
Other autoimmune disorders
[edit]Celiac disease
[edit]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]
Systemic lupus erythematosus
[edit]Systemic lupus erythematosus and pregnancy confers an increased rate of fetal death in utero and spontaneous abortion (miscarriage), as well as of neonatal lupus.
Behçet's disease
[edit]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
[edit]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
[edit]Depression in pregnancy
[edit]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
[edit]Asthma
[edit]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
[edit]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
[edit]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
[edit]The following conditions may also become worse or be a potential risk to the pregnancy:
- Cancer[MMHE 2]
- Chronic hypertension[MMHE 3]
- Cirrhosis[MMHE 4]
- Congenital disorders that may be passed on to offspring
- Heart defects, especially primary pulmonary hypertension and Eisenmenger's syndrome[MMHE 5]
- Kidney disorders[MMHE 6]
- Mental health.
- Depression has been linked to higher rates of preterm delivery.[38]
- Respiratory disorders and diseases (associated, for example, with placental abruption)[39]
- Seizure disorders[MMHE 7]
- Structural abnormalities in the cervix
- Structural abnormalities in the uterus
- Viral hepatitis[MMHE 8]
References
[edit]- ^ Bramham, Kate; Parnell, Bethany; Nelson-Piercy, Catherine; Seed, Paul T; Poston, Lucilla; Chappell, Lucy C (2014-04-15). "Chronic hypertension and pregnancy outcomes: systematic review and meta-analysis". The BMJ. 348: g2301. doi:10.1136/bmj.g2301. ISSN 0959-8138. PMC 3988319. PMID 24735917.
- ^ Al Khalaf, Sukainah Y.; O'Reilly, Éilis J.; Barrett, Peter M.; B. Leite, Debora F.; Pawley, Lauren C.; McCarthy, Fergus P.; Khashan, Ali S. (2021-05-04). "Impact of Chronic Hypertension and Antihypertensive Treatment on Adverse Perinatal Outcomes: Systematic Review and Meta-Analysis". Journal of the American Heart Association. 10 (9): e018494. doi:10.1161/JAHA.120.018494. ISSN 2047-9980. PMC 8200761. PMID 33870708.
- ^ "Pregnancy complications increase the risk of heart attacks and stroke in women with high blood pressure". NIHR Evidence (Plain English summary). National Institute for Health and Care Research. 2023-11-21. doi:10.3310/nihrevidence_60660.
- ^ Al Khalaf, Sukainah; Chappell, Lucy C.; Khashan, Ali S.; McCarthy, Fergus P.; O'Reilly, Éilis J. (12 May 2023). "Association Between Chronic Hypertension and the Risk of 12 Cardiovascular Diseases Among Parous Women: The Role of Adverse Pregnancy Outcomes". Hypertension. 80 (7): 1427–1438. doi:10.1161/HYPERTENSIONAHA.122.20628. ISSN 0194-911X.
- ^ Webster, Louise M.; Conti-Ramsden, Frances; Seed, Paul T.; Webb, Andrew J.; Nelson-Piercy, Catherine; Chappell, Lucy C. (2017-05-17). "Impact of Antihypertensive Treatment on Maternal and Perinatal Outcomes in Pregnancy Complicated by Chronic Hypertension: A Systematic Review and Meta-Analysis". Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease. 6 (5). doi:10.1161/JAHA.117.005526. ISSN 2047-9980. PMC 5524099. PMID 28515115.
- ^ a b c Spencer, L; Bubner, T; Bain, E; Middleton, P (21 September 2015). "Screening and subsequent management for thyroid dysfunction pre-pregnancy and during pregnancy for improving maternal and infant health". The Cochrane Database of Systematic Reviews. 2015 (9): CD011263. doi:10.1002/14651858.CD011263.pub2. PMC 9233937. PMID 26387772.
- ^ a b Page 264 in: Gresele, Paolo (2008). Platelets in hematologic and cardiovascular disorders: a clinical handbook. Cambridge, UK: Cambridge University Press. ISBN 978-0-521-88115-9.
- ^ K E Ugen; J J Goedert; J Boyer; Y Refaeli; I Frank; W V Williams; A Willoughby; S Landesman; H Mendez; A Rubinstein (June 1992). "Vertical transmission of human immunodeficiency virus (HIV) infection. Reactivity of maternal sera with glycoprotein 120 and 41 peptides from HIV type 1". J Clin Invest. 89 (6): 1923–1930. doi:10.1172/JCI115798. PMC 295892. PMID 1601999.
- ^ Fawzi WW, Msamanga G, Hunter D, Urassa E, Renjifo B, Mwakagile D, Hertzmark E, Coley J, Garland M, Kapiga S, Antelman G, Essex M, Spiegelman D (1999). "Randomized trial of vitamin supplements in relation to vertical transmission of HIV-1 in Tanzania". Journal of Acquired Immune Deficiency Syndromes. 23 (3): 246–254. doi:10.1097/00042560-200003010-00006. PMID 10839660. S2CID 35936352.
- ^ Lee MJ, Hallmark RJ, Frenkel LM, Del Priore G (1998). "Maternal syphilis and vertical perinatal transmission of human immunodeficiency virus type-1 infection". International Journal of Gynecology & Obstetrics. 63 (3): 246–254. doi:10.1016/S0020-7292(98)00165-9. PMID 9989893. S2CID 22297001.
- ^ a b Health Care Guideline: Routine Prenatal Care. Fourteenth Edition. Archived 2008-07-05 at the Wayback Machine By the Institute for Clinical Systems Improvement. July 2010.
- ^ Sobel, JD (9 June 2007). "Vulvovaginal candidosis". Lancet. 369 (9577): 1961–71. doi:10.1016/S0140-6736(07)60917-9. PMID 17560449. S2CID 33894309.
- ^ Roberts, C. L.; Rickard, K.; Kotsiou, G.; Morris, J. M. (2011). "Treatment of asymptomatic vaginal candidiasis in pregnancy to prevent preterm birth: An open-label pilot randomized controlled trial". BMC Pregnancy and Childbirth. 11: 18. doi:10.1186/1471-2393-11-18. PMC 3063235. PMID 21396090.
- ^ Ratcliffe, Stephen D.; Baxley, Elizabeth G.; Cline, Matthew K. (2008). Family Medicine Obstetrics. Elsevier Health Sciences. p. 273. ISBN 978-0323043069.
- ^ "Bacterial Vaginosis Treatment and Care". Centers of Disease Control and Prevention. Retrieved 24 October 2020.
- ^ Bacterial vaginosis from National Health Service, UK. Page last reviewed: 03/10/2013
- ^ Tersigni, C.; Castellani, R.; de Waure, C.; Fattorossi, A.; De Spirito, M.; Gasbarrini, A.; Scambia, G.; Di Simone, N. (2014). "Celiac disease and reproductive disorders: meta-analysis of epidemiologic associations and potential pathogenic mechanisms". Human Reproduction Update. 20 (4): 582–593. doi:10.1093/humupd/dmu007. hdl:10807/56796. ISSN 1355-4786. PMID 24619876.
- ^ Saccone G, Berghella V, Sarno L, Maruotti GM, Cetin I, Greco L, Khashan AS, McCarthy F, Martinelli D, Fortunato F, Martinelli P (Oct 9, 2015). "Celiac disease and obstetric complications: a systematic review and metaanalysis". Am J Obstet Gynecol. 214 (2): 225–34. doi:10.1016/j.ajog.2015.09.080. hdl:11369/330101. PMID 26432464.
- ^ "The Gluten Connection". Health Canada. May 2009. Retrieved 1 October 2013.
- ^ a b Uzun, 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. doi:10.1111/j.1346-8138.2003.tb00423.x. PMID 12928538. S2CID 12860697.
- ^ a b Jadaon, J.; Shushan, A.; Ezra, Y.; Sela, H. Y.; Ozcan, C.; Rojansky, N. (2005). "Behcet's disease and pregnancy". Acta Obstetricia et Gynecologica Scandinavica. 84 (10): 939–944. doi:10.1111/j.0001-6349.2005.00761.x. PMID 16167908. S2CID 22363654.
- ^ a b Compston A, Coles A (October 2008). "Multiple sclerosis". Lancet. 372 (9648): 1502–17. doi:10.1016/S0140-6736(08)61620-7. PMID 18970977. S2CID 195686659.
- ^ Multiple Sclerosis: Pregnancy Q&A Archived 2013-10-19 at the Wayback Machine from Cleveland Clinic, retrieved January 2014.
- ^ Ramagopalan, S. V.; Guimond, C.; Criscuoli, M.; Dyment, D. A.; Orton, S. M.; Yee, I. M.; Ebers, G. C.; Sadovnick, D. (2010). "Congenital Abnormalities and Multiple Sclerosis". BMC Neurology. 10: 115. doi:10.1186/1471-2377-10-115. PMC 3020672. PMID 21080921.
- ^ a b c Pearlstein, Teri (2015-07-01). "Depression during Pregnancy". Best Practice & Research Clinical Obstetrics & Gynaecology. 29 (5): 754–764. doi:10.1016/j.bpobgyn.2015.04.004. ISSN 1521-6934. PMID 25976080. S2CID 2932772.
- ^ Becker, Madeleine; Weinberger, Tal; Chandy, Ann; Schmukler, Sarah (2016-02-15). "Depression During Pregnancy and Postpartum". Current Psychiatry Reports. 18 (3): 32. doi:10.1007/s11920-016-0664-7. ISSN 1535-1645. PMID 26879925. S2CID 38045296.
- ^ Kwon, Helen L.; Triche, Elizabeth W.; Belanger, Kathleen; Bracken, Michael B. (2006-02-01). "The Epidemiology of Asthma During Pregnancy: Prevalence, Diagnosis, and Symptoms". Immunology and Allergy Clinics of North America. 26 (1): 29–62. doi:10.1016/j.iac.2005.11.002. ISSN 0889-8561. PMID 16443142.
- ^ Murphy, V. E.; Namazy, J. A.; Powell, H.; Schatz, M.; Chambers, C.; Attia, J.; Gibson, P. G. (2011). "A meta-analysis of adverse perinatal outcomes in women with asthma". BJOG: An International Journal of Obstetrics & Gynaecology. 118 (11): 1314–1323. doi:10.1111/j.1471-0528.2011.03055.x. hdl:1959.13/1052131. ISSN 1471-0528. PMID 21749633. S2CID 30009033.
- ^ Mendola, Pauline; Laughon, S. Katherine; Männistö, Tuija I.; Leishear, Kira; Reddy, Uma M.; Chen, Zhen; Zhang, Jun (February 2013). "Obstetric complications among US women with asthma". American Journal of Obstetrics and Gynecology. 208 (2): 127.e1–127.e8. doi:10.1016/j.ajog.2012.11.007. ISSN 0002-9378. PMC 3557554. PMID 23159695.
- ^ a b Dombrowski, Mitchell P.; Schatz, Michael; Wise, Robert; Momirova, Valerija; Landon, Mark; Mabie, William; Newman, Roger B.; McNellis, Donald; Hauth, John C.; Lindheimer, Marshall; Caritis, Steve N.; Leveno, Kenneth J.; Meis, Paul; Miodovnik, Menachem; Wapner, Ronald J.; Paul, Richard H.; Varner, Michael W.; o'Sullivan, Mary Jo; Thurnau, Gary R.; Conway, Deborah L. (2004). "Asthma During Pregnancy". Obstetrics & Gynecology. 103 (1): 5–12. doi:10.1097/01.AOG.0000103994.75162.16. PMID 14704237. S2CID 43265653.
- ^ a b Ali, Z.; Hansen, A. V.; Ulrik, C. S. (2016-05-18). "Exacerbations of asthma during pregnancy: Impact on pregnancy complications and outcome". Journal of Obstetrics and Gynaecology. 36 (4): 455–461. doi:10.3109/01443615.2015.1065800. ISSN 0144-3615. PMID 26467747. S2CID 207436121.
- ^ Enriquez, Rachel; Griffin, Marie R.; Carroll, Kecia N.; Wu, Pingsheng; Cooper, William O.; Gebretsadik, Tebeb; Dupont, William D.; Mitchel, Edward F.; Hartert, Tina V. (September 2007). "Effect of maternal asthma and asthma control on pregnancy and perinatal outcomes". Journal of Allergy and Clinical Immunology. 120 (3): 625–630. doi:10.1016/j.jaci.2007.05.044. ISSN 0091-6749. PMID 17658591.
- ^ Busse, William W. (January 2005). "NAEPP Expert Panel ReportManaging Asthma During Pregnancy: Recommendations for Pharmacologic Treatment—2004 Update". Journal of Allergy and Clinical Immunology. 115 (1): 34–46. doi:10.1016/j.jaci.2004.10.023. ISSN 0091-6749. PMID 15637545.
- ^ Bonham, Catherine A.; Patterson, Karen C.; Strek, Mary E. (February 2018). "Asthma Outcomes and Management During Pregnancy". Chest. 153 (2): 515–527. doi:10.1016/j.chest.2017.08.029. ISSN 0012-3692. PMC 5815874. PMID 28867295.
- ^ N.C. Thomson, G. Vallance, in Encyclopedia of Respiratory Medicine, 2006, Pages 206-215
- ^ Neil Pearce, Jeroen Douwes, in Women and Health (Second Edition), 2013
- ^ a b c Akhtar, M. A.; Saravelos, S. H.; Li, T. C.; Jayaprakasan, K. (2020). "Reproductive Implications and Management of Congenital Uterine Anomalies". BJOG: An International Journal of Obstetrics & Gynaecology. 127 (5): e1–e13. doi:10.1111/1471-0528.15968. ISSN 1471-0528. PMID 31749334.
- ^ Li, D; Liu, L; Odouli, R (2009). "Presence of depressive symptoms during early pregnancy and the risk of preterm delivery: a prospective cohort study". Human Reproduction. 24 (1): 146–153. doi:10.1093/humrep/den342. PMID 18948314.
- ^ 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. doi:10.1016/j.ajog.2006.07.027. PMID 17000252.
- ^ Dombrowski, MP (2006). "Asthma and pregnancy". Obstetrics and Gynecology. 108 (3 Pt 1): 667–81. doi:10.1097/01.AOG.0000235059.84188.9c. PMID 16946229.
- ^ Louik, C; Schatz, M; Hernández-Díaz, S; Werler, MM; Mitchell, AA (2010). "Asthma in Pregnancy and its Pharmacologic Treatment". Annals of Allergy, Asthma & Immunology. 105 (2): 110–7. doi:10.1016/j.anai.2010.05.016. PMC 2953247. PMID 20674820.
- ^ Merck. "Overview of Disease During Pregnancy". Merck Manual Home Health Handbook. Merck Sharp & Dohme.
- ^ Merck. "Cancer during pregnancy". Merck Manual Home Health Handbook. Merck Sharp & Dohme. Archived from the original on 2015-03-28. Retrieved 2013-08-13.
- ^ Merck. "High blood pressure during pregnancy". Merck Manual Home Health Handbook. Merck Sharp & Dohme. Archived from the original on 2015-03-02. Retrieved 2013-08-13.
- ^ Merck. "Liver and gallbladder disorders during pregnancy". Merck Manual Home Health Handbook. Merck Sharpe & Dohme. Archived from the original on 2015-03-16. Retrieved 2013-08-13.
- ^ Merck. "Heart disorders during pregnancy". Merck Manual Home Health Handbook. Merck Sharp & Dohme. Archived from the original on 2015-02-21. Retrieved 2013-08-13.
- ^ Merck. "Kidney disorders during pregnancy". Merck Manual Home Health Handbook. Merck Sharp & Dohme. Archived from the original on 2015-02-21. Retrieved 2013-08-13.
- ^ Merck. "Seizure disorders during pregnancy". Merck Manual Home Health Handbook. Merck Sharp & Dohme. Archived from the original on 2015-02-21. Retrieved 2013-08-13.
- ^ Merck. "Liver and gallbladder disorders during pregnancy". Merck Manual Home Health Handbook. Merck Sharpe & Dohme. Archived from the original on 2015-03-16. Retrieved 2013-08-13.