MODE OF DELIVERY AND GESTATIONAL-AGE INFLUENCE PERINATAL HIV-1 TRANSMISSION

Some data suggest that cesarean section reduces mother-to-child HIV-1 transmission. To assess the influence of mode of delivery and other ma ternal and infant factors on the rate of transmission, we analyzed the data of 1,624 children prospectively followed from birth. Of these, a t the last visit 1,033 were > 18 months of age or would have been had they not died of HIV-related illness. Among the 975 first singleton ch ildren, 180 [18.5%; 95% confidence limits (CL), 16.1-20.9] acquired in fection, as did 8 of 56 (14.3%; 95% CL, 5.1-23.5) second-born children . Multivariate stepwise analysis showed that vaginal delivery and deve lopment of symptoms in the mother were significantly and independently associated with a higher transmission rate (vaginal delivery: odds ra tio, 1.69; 95% CL, 1.14-2.5; symptoms: odds ratio, 1.61; 95% CL, 1.12- 2.3), In contrast, a history of maternal drug use, birth weight, breas tfeeding (only 37 infants were breast-fed), and child's sex did not ha ve a significant impact on viral transmission. The percentage of infec ted children was highest (30.7%) among very premature infants (less th an or equal to 32 weeks of gestation); this significant trend subseque ntly decreased to 11.9% at the week 42 (p < 0.001), suggesting a paral lel reduction in peripartum transmission. The reduced rate of infectio n observed in infants born by cesarean section underlines the urgent n eed for randomized controlled trials to evaluate the protective role o f surgical delivery in preventing perinatal HIV-1 transmission.