Elective caesarean-section versus vaginal delivery in prevention of vertical HIV-1 transmission: a randomised clinical trial

Background Results from observational studies suggest that caesarean-sectio n delivery may reduce the risk of mother-to-child transmission of HIV-1 inf ection in comparison with vaginal delivery. We carried out a randomised cli nical trial to address this issue and to assess the extent of postdelivery complications. Methods Eligible women were between 34 and 36 weeks of pregnancy, with a co nfirmed diagnosis of HIV-1 infection, and without an indication for caesare an-section delivery or a contraindication to this mode of delivery. Women w ere randomly assigned elective caesarean-section delivery at 38 weeks of pr egnancy or vaginal delivery. An infant was classified as uninfected if he o r she became negative for antibody to HIV-1 by age 18 months or was negativ e for virus by PCR or culture on at least two occasions, with no clinical, immunological, or viral evidence of infection. From 1993, to March, 1998, 4 36 women were randomised. Findings We present the results of an analysis updated to November, 1998, w ith data on the infection status of 370 infants. Three (1.8%) of 170 infant s born to women assigned caesarean-section delivery were infected, compared with 21 (10.5%) of 200 born to women assigned vaginal delivery (p<0.001). Seven (3.4%) of 203 infants of women who actually gave birth by caesarean s ection were infected compared with 15 (10.2%) of 167 born vaginally (p=0.00 9). There were few postpartum complications and no serious adverse events i n either group. Interpretation Our findings provide evidence that elective caesarean-sectio n delivery significantly lowers the risk of mother-to-child transmission of HIV-1 infection without a significantly increased risk of complications fo r the mother.