FACTORS PREDICTIVE OF MATERNAL-FETAL TRANSMISSION OF HIV-1 - PRELIMINARY-ANALYSIS OF ZIDOVUDINE GIVEN DURING PREGNANCY AND OR DELIVERY/

Objective.-To assess maternal risk factors potentially influencing ver tical transmission of human immunodeficiency virus, type 1 (HIV-1), in cluding maternal CD4 cell count; presence of immune complex dissociate d (ICD) p24 antigen; maternal zidovudine therapy during pregnancy and/ or delivery, complications of pregnancy, such as preterm labor and bir th; and obstetric events during labor and delivery, such as duration o f labor, mode of delivery, chorioamnionitis, and maternal blood exposu re. Design and Setting.-A nonrandomized prospective cohort study at a university medical center and two general hospital affiliates. Patient s.-Sixty-three HIV-1-seropositive pregnant women and their 68 infants. Intervention.-Twenty-six mothers received zidovudine therapy during p regnancy and/or during labor and delivery. Main Outcome Measure.-HIV-1 infection status of the infant. Results.-Thirteen of the 68 infants w ere vertically infected with HIV-1. Mothers with events involving feta l exposure to maternal blood were more likely to transmit infection (f our [31%] of 13 vs three [5%] of 55, P=.02), as were women with plasma ICD p24 antigenemia at delivery (six [67%] of nine vs 11 [25%] of 44, P=.02). Zidovudine treatment was associated with a significant reduct ion in vertical transmission (one [4%] of 26 mothers treated with zido vudine vs 12 [29%] of 42 mothers not treated with zidovudine, P=.01), There was a significant protective effect of zidovudine treatment desp ite lower mean absolute CD4 cell counts (0.37x10(9)/L) in the 24 zidov udine-treated nontransmitters and in the nine non-zidovudine-treated t ransmitters (0.37x10(9)/L) than in the 24 non-zidovudine-treated nontr ansmitters (0.62x10(9)/L) (P=.008). Conclusion.-Maternal-fetal HIV-1 t ransmission is multifactorial, with increased risk associated both wit h ICD p24 antigenemia at term and with intrapartum events that increas e fetal exposure to maternal blood. Zidovudine therapy given during pr egnancy and/or labor and delivery was associated with a significant re duction in vertical transmission. These data suggest that the benefici al effects of zidovudine therapy in reducing maternal-fetal HIV-1 tran smission recently found in protocol 076 of the placebo-controlled Acqu ired Immunodeficiency Syndrome Clinical Trials Group Study may extend to women with lower CD4 cell counts and suggest that prolonged treatme nt of infants may not be necessary.