Pregnant women infected with HIV-1 are randomized to 1 of 4 study arms and receive either NVP or its placebo, or AZT or its placebo. Mothers in the NVP group receive a single dose of NVP or placebo at the onset of labor and are followed to 6 to 8 weeks after delivery. Infants born to these mothers receive at 48 to 72 hours post-delivery or discharge, whichever comes first, a regimen of the same treatment (NVP or placebo) given to the mother. Infants are followed for 18 months post-delivery by clinical and laboratory evaluation to determine toxicity, evidence of HIV-1 infection, and clinical disease progression.