Chapter 007. Medical Disorders during Pregnancy (Part 8) Rubella (See also Chap. 186) Rubella virus is a known teratogen; first-trimester rubella carries a high risk of fetal anomalies, though the risk decreases significantly later in pregnancy. Congenital rubella may be diagnosed by percutaneous umbilical blood sampling with the detection of IgM antibodies in fetal blood. All pregnant women should be screened for their immune status to rubella. Indeed, all women of childbearing age, regardless of pregnancy status, should have their immune status for rubella verified and be immunized if necessary. The incidence of congenital rubella in the United States is extremely low. Herpesvirus (See also Chap. 172) The acquisition of genital herpes during pregnancy is associated with spontaneous abortion, prematurity, and congenital and neonatal herpes. A recent cohort study of pregnant women without evidence of previous herpes infection demonstrated that ~2% of the women acquired a new herpes infection during the pregnancy. Approximately 60% of the newly infected women had no clinical symptoms. Infection occurred equally in all three trimesters. If herpes seroconversion occurred early in pregnancy, the risk of transmission to the newborn was very low. In women who acquired genital herpes shortly before delivery, the risk of transmission was high. The risk of active genital herpes lesions at term can be reduced by prescribing acyclovir for the last 4 weeks of pregnancy to women who have had their first episode of genital herpes during the pregnancy. Herpesvirus infection in the newborn can be devastating. Disseminated neonatal herpes carries with it high mortality and morbidity rates from CNS involvement. It is recommended that pregnant women with active genital herpes lesions at the time of presentation in labor be delivered by cesarean section. Parvovirus (See also Chap. 177) Parvovirus infection (human parvovirus B19) may occur during pregnancy. It rarely causes sequelae, but susceptible women infected during pregnancy may be at risk for fetal hydrops secondary to erythroid aplasia and profound anemia. HIV Infection (See also Chap. 182) The predominant cause of HIV infection in children is transmission of the virus from the mother to the newborn during the perinatal period. Exposures, which increase the risk of mother-to-child transmission, include vaginal delivery, preterm delivery, trauma to the fetal skin, and maternal bleeding. Additionally, recent infection with high maternal viral load, low maternal CD4+ T cell count, prolonged labor, prolonged length of membrane rupture, and the presence of other genital tract infections, such as syphilis or herpes, increase the risk of transmission. Breast-feeding may also transmit HIV to the newborn and is therefore contraindicated in most developed countries for HIV- infected mothers. There is no clear evidence to suggest that the course of HIV disease is altered by pregnancy. There is also no clear evidence to suggest that uncomplicated HIV disease adversely impacts pregnancy other than by its inherent infection risk. HIV Infection in Pregnancy: Treatment The majority of cases of mother-to-child (vertical) transmission of HIV-1 occur during the intrapartum period. Mechanisms of vertical transmission include infection after rupture of the membranes and direct contact of the fetus with infected secretions or blood from the maternal genital tract. Zidovudine (ZDV) administered during pregnancy and labor and to the newborn reduces the risk of vertical transmission by 70%. Cesarean section is associated with additional risk reduction compared to vaginal delivery, especially in women with a viral load >1000 copies/mL. Regardless of the mode of delivery, intrapartum ZDV should be provided. Summary Maternal mortality has decreased steadily during the past 70 years. The maternal death rate has decreased from nearly 600/100,000 live births in 1935 to 8/100,00 live births in 2002. The most common causes of maternal death in the United States today are, in decreasing order of frequency, pulmonary embolism, obstetric hemorrhage, hypertension, sepsis, cardiovascular conditions including peripartum cardiomyopathy, and ectopic pregnancy. With improved diagnostic and therapeutic modalities as well as with advances in the treatment of infertility, more patients with medical complications will be seeking, and be in need of, complex obstetric care. Improving outcome of pregnancy in these women will be best obtained by assembling a team of internists, specialists in maternal-fetal medicine (high-risk obstetrics), and anesthesiologists to counsel these patients about the risks of pregnancy and to plan their treatment prior to conception. The importance of preconception counseling cannot be overstated. It is the responsibility of all physicians caring for women in the reproductive age group to assess their patient's reproductive plans as part of their overall health evaluation. Further Readings Alexander EK et al: Timing and magnitude of increases in levothyroxine requirements during pregnancy in women with hypo thyroidism. N Engl J Med 351:292, 2005 Bates SM et al: Use of antithrombotic agents during pregnancy: The Seventh ACCP Conference on antithrombotic and thrombolytic therapy. Chest 126:627S, 2004 Buchanan TA, Xiang AH: Gestational diabetes mellitus. J C lin Invest 115:485, 2005 [PMID: 15765129] Crowther CA et al: Effect of treatment of gestational diabetes mellitus on pregnancy outcomes. N Engl J Med 352:2477, 2005 [PMID: 15951574] Deneux-Tharaux C et al: Underreporting of pregnancy-related mortality in the United States and Europe. Obstet Gynecol 106:684, 2005 [PMID: 16199622] Kaaja RJ, Greer IA: Manifestations of chronic disease during pregnancy. JAMA 294:2751, 2005 [PMID: 16333011] Levine RJ: Circulating angiogenic factors and the risk of preecl ampsia. N Engl J Med 350:672, 2004 [PMID: 14764923] Magee LA et al: Hydralazine for treatment of severe hypertension in pregnancy: Meta-analysis. BMJ 327:955, 2003 [PMID: 14576246] Sibai BM: Chronic hypertension in pregnancy. Obstet Gynecol 100:369, 2002 [PMID: 12151166] The Magpie Trial Collaborative Group: Do women with preeclampsia, and their babies, benefit from magnesium sulfate? The Magpie Trial: A randomised placebo-controlled trial. Lancet 359:1877, 2002 . Chapter 007. Medical Disorders during Pregnancy (Part 8) Rubella (See also Chap. 186) Rubella virus is a known teratogen;. Parvovirus infection (human parvovirus B19) may occur during pregnancy. It rarely causes sequelae, but susceptible women infected during pregnancy may be at risk for fetal hydrops secondary to. in levothyroxine requirements during pregnancy in women with hypo thyroidism. N Engl J Med 351:292, 2005 Bates SM et al: Use of antithrombotic agents during pregnancy: The Seventh ACCP Conference