Data from a prospective study undertaken at an urban hospital in Durban, South Africa, were used to investigate associations between maternal-infant HIV transmission, mode of delivery, and specific circumstances of cesarean deliveries. A total of 141 children of HIV-infected women were followed until the children were 15 months of age to determine their HIV status. supplementary data were collected from obstetric records, masked to the HIV status of the children. In this African and predominantly breast-fed population, infants delivered vaginally were more likely to be infected (39.8% infected) than were infants delivered by cesarean section [22.9% infected; odds ratio (OR), 0.45; 95% confidence interval (CI), 0.20-0.99]. There were no significant differences between cesarean deliveries undertaken following prior rupture of membranes and those undertaken with membranes intact, but numbers for this comparison were small. Singleton cesarean deliveries without concurrent obstetric complications had lower rates of transmission than did vaginal deliveries (OR, 0.20; 95% CI, 0.04-0.94). These results suggest that certain intrapartum events may modify the risk of HIV transmission and highlight the importance of collecting more detailed intrapartum information in order to clarify the route by which mode of delivery may be associated with maternal-infant HIV transmission.
PIP: In South Africa, researchers tried to follow 229 mother-child pairs attending the prenatal care clinic of and delivering at King Edward VIII Hospital in Durban until the index child was at least 15 months old. They examined the associations between mode of delivery and maternal-infant HIV transmission. Outcomes were known for 136 women and their 141 children. There were no significant differences between these mother-child pairs and those lost to follow-up in terms of maternal age, parity, weight at first prenatal visit, number of prenatal visits, or the detection of other sexually transmitted diseases, nor in the child's gender, birth weight, gestation, circumstances of delivery, or feeding practices. Children delivered by cesarean section were less likely to develop HIV infection than those delivered vaginally (22.9% vs. 39.8%; odds ratio [OR] = 0.45 for univariate analysis and 0.41 for multivariate analysis). Singleton cesarean deliveries without concurrent obstetric complications were significantly less likely to develop HIV infection than vaginal deliveries (11.7% vs. 39.8%; OR = 0.20; p 0.5). The HIV transmission rates in the other cesarean section subgroups were not significantly different than those in the vaginal delivery group. They were still lower, however. Survival to 18 months was not significantly different between the nine HIV infected infants delivered by cesarean section and their vaginally delivered counterparts (67% vs. 74%; p = 0.7). These findings indicate that some intrapartum events may influence the risk of HIV transmission. They highlight the need to collect more detailed intrapartum information to identify the route by which mode of delivery may be associated with maternal-infant HIV transmission. The intrapartum events that may have influenced HIV transmission in this study include ruptured membranes, twin delivery, and intrapartum hemorrhage.