Administration of an antiretroviral agent to a pregnant woman in theory could reduce the risk of neonatal infection by reducing the exposure of the fetus to maternal virus, or by prophylaxis of the fetus prior to exposure. Because it is postulated that intense exposure of a potentially uninfected fetus to HIV present in maternal blood and genital tract secretions occurs during parturition, the design of this study includes intrapartum administration of ZDV followed by six weeks of oral ZDV to the infant.