After AIDS Clinical Trial 076: The Changing Pattern of Zidovudine Use during Pregnancy, and the Subsequent Reduction in the Vertical Transmission of Human Immunodeficiency Virus in a Cohort of Infected Women and Their Infants

To determine the impact of the AIDS Clinical Trials Group (ACTG) Protocol 076 results on the subsequent use of zidovudine during pregnancy and the transmission rate of human immunodeficiency virus (HIV) in a cohort of mother-infant pairs (Women and Infants Transmission Study), a retrospective analysis was done. Transmission rates were calculated by simple proportion for infants with at least 6 months of follow-up, stratified by date of birth (n = 453 born on or before 1 March 1994; n = 103 born after 1 March 1994). Transmission rates decreased from 19% to 8% (P = .005, Fisher's exact test). Zidovudine use increased during pregnancy (22% vs. 89%) and in newborns (1% vs. 79%). Both cohorts were similar with respect to maternal immunosuppression, mode of delivery, and demographics. In summary, in a perinatal HIV observational study, the release of results of ACTG Protocol 076 was associated with an increase in zidovudine use during pregnancy and a concomitant decline in HIV transmission from mothers to infants.