Human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome in women of childbearing age are increasing rapidly in the United States. Perinatal transmission can occur during pregnancy, delivery or breast feeding. Because 90 percent of pediatric HIV infections are caused by perinatal transmission, the U.S. Public Health Service has recommended that all pregnant women be offered HIV counseling and testing. Factors that influence perinatal transmission include high maternal viral load, low maternal CD4 count, prolonged rupture of the membranes, premature delivery and symptomatic maternal HIV infection. The results of a recent clinical trial demonstrate that if HIV-infected women become pregnant, the use of zidovudine during the prenatal, intrapartum and neonatal periods can decrease by two-thirds the likelihood of HIV transmission to the baby. The U.S. Public Health Service, in conjunction with the American Academy of Family Physicians, has strongly recommended expanding the current noncoercive, voluntary HIV testing to include routine testing of all pregnant women.