Analysis of the maternal components of the AIDS clinical trial group 076 zidovudine regimen in the prevention of mother-to-infant transmission of human immunodeficiency virus type 1.

To gain insight into the protective effects of the three components of the zidovudine regimen used in AIDS Clinical Trial Group (ACTG) 076 on mother-to-infant transmission of human immunodeficiency virus (HIV) type 1, 188 zidovudine-treated women and their untreated infants from five HIV-1 obstetric centers were retrospectively studied. The overall rate of mother-to-infant transmission was 12.3% (95% confidence interval [CI], 7.9%-18.0%). When the 38 women with <200 CD4 cells/microL were excluded, the mother-to-infant transmission rate was 8.8% (95% CI, 4.6%-14.8%). This rate compares favorably with the 8.3% transmission in the zidovudine arm of the ACTG 076 study. Apart from low (<200/microL) maternal CD4 cells (P = .016), no factors, including the duration of zidovudine therapy during gestation and intravenous administration of zidovudine during labor, affected the rate of mother-to-infant transmission. These findings suggest that antenatal oral zidovudine may be as effective as antenatal oral plus intravenous zidovudine during labor and the three-component ACTG 076 regimen in decreasing mother-to-infant HIV-1 transmission.