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...
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Chapter 007. Medical Disorders during Pregnancy (Part 8) Chapter 007. Medical Disorders during Pregnancy (Part 8) Rubella (See also Chap. 186) Rubella virus is a known teratogen; first-trimesterrubella carries a high risk of fetal anomalies, though the risk decreasessignificantly later in pregnancy. Congenital rubella may be diagnosed bypercutaneous umbilical blood sampling with the detection of IgM antibodies infetal blood. All pregnant women should be screened for their immune status torubella. Indeed, all women of childbearing age, regardless of pregnancy status,should have their immune status for rubella verified and be immunized ifnecessary. The incidence of congenital rubella in the United States is extremelylow. Herpesvirus (See also Chap. 172) The acquisition of genital herpes during pregnancy isassociated with spontaneous abortion, prematurity, and congenital and neonatalherpes. A recent cohort study of pregnant women without evidence of previousherpes infection demonstrated that ~2% of the women acquired a new herpesinfection during the pregnancy. Approximately 60% of the newly infected womenhad no clinical symptoms. Infection occurred equally in all three trimesters. Ifherpes seroconversion occurred early in pregnancy, the risk of transmission to thenewborn was very low. In women who acquired genital herpes shortly beforedelivery, the risk of transmission was high. The risk of active genital herpeslesions at term can be reduced by prescribing acyclovir for the last 4 weeks ofpregnancy to women who have had their first episode of genital herpes during thepregnancy. Herpesvirus infection in the newborn can be devastating. Disseminatedneonatal herpes carries with it high mortality and morbidity rates from CNSinvolvement. It is recommended that pregnant women with active genital herpeslesions at the time of presentation in labor be delivered by cesarean section. Parvovirus (See also Chap. 177) Parvovirus infection (human parvovirus B19) mayoccur during pregnancy. It rarely causes sequelae, but susceptible women infectedduring pregnancy may be at risk for fetal hydrops secondary to erythroid aplasiaand profound anemia. HIV Infection (See also Chap. 182) The predominant cause of HIV infection in children istransmission of the virus from the mother to the newborn during the perinatalperiod. Exposures, which increase the risk of mother-to-child transmission,include vaginal delivery, preterm delivery, trauma to the fetal skin, and maternalbleeding. Additionally, recent infection with high maternal viral load, lowmaternal CD4+ T cell count, prolonged labor, prolonged length of membranerupture, and the presence of other genital tract infections, such as syphilis orherpes, increase the risk of transmission. Breast-feeding may also transmit HIV tothe newborn and is therefore contraindicated in most developed countries for HIV-infected mothers. There is no clear evidence to suggest that the course of HIVdisease is altered by pregnancy. There is also no clear evidence to suggest thatuncomplicated HIV disease adversely impacts pregnancy other than by its inherentinfection risk. HIV Infection in Pregnancy: Treatment The majority of cases of mother-to-child (vertical) transmission of HIV-1occur during the intrapartum period. Mechanisms of vertical transmission includeinfection after rupture of the membranes and direct contact of the fetus withinfected secretions or blood from the maternal genital tract. Zidovudine (ZDV)administered during pregnancy and labor and to the newborn reduces the risk ofvertical transmission by 70%. Cesarean section is associated with additional riskreduction compared to vaginal delivery, especially in women with a viral load>1000 copies/mL. Regardless of the mode of delivery, intrapartum ZDV should beprovided. Summary Maternal mortality has decreased steadily during the past 70 years. Thematernal death rate has decreased from nearly 600/100,000 live births in 1935 to8/100,00 live births in 2002. The most common causes of maternal death in theUnited States today are, in decreasing order of frequency, pulmonary embolism,obstetric hemorrhage, hypertension, sepsis, cardiovascular conditions includingperipartum cardiomyopathy, and ectopic pregnancy. With improved diagnosticand 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 bebest obtained by assembling a team of internists, specialists in maternal-fetalmedicine (high-risk obstetrics), and anesthesiologists to counsel these patientsabout the risks of pregnancy and to plan their treatment prior to conception. Theimportance of preconception counseling cannot be overstated. It is theresponsibility of all physicians caring for women in the reproductive age group toassess their patients reproductive plans as part of their overall health evaluation. Further Readings Alexander EK et al: Timing and magnitude of increases in levothyroxinerequirements during pregnancy in women with hypothyroidism. N Engl J Med351:292, 2005 Bates SM et al: Use of antithrombotic agents during pregnancy: TheSeventh ACCP Conference on antithrombotic and thrombolytic therapy. Chest126:627S, 2004 Buchanan TA, Xiang AH: Gestational diabetes mellitus. J Clin Invest115:485, 2005 [PMID: 15765129] Crowther CA et al: Effect of treatment of gestational diabetes mellitus onpregnancy outcomes. N Engl J Med 352:2477, 2005 [PMID: 15951574] Deneux-Tharaux C et al: Underreporting of ...