Objective: Perinatal transmission of the human immunodeficiency virus is the main pathway for children to become infected with this virus; however, the relative contribution and timing of this transmission, whether transplacental or by exposure through the birth process, have not yet been elucidated. An obvious question is whether the mode of delivery has an impact on this transmission rate. However, a routine cesarean section will primarily diminish the duration of exposure of maternal bodily fluids to the neonate but does not prevent the baby from being exposed to maternal blood coming from the uterine incision. The purpose of this study was to determine whether the rate of perinatal transmission of human immunodeficiency virus could be significantly lowered by delivering the baby with minimal to no exposure to maternal blood or bodily fluids by the use of a surgical technique termed a "bloodless cesarean section."
Study design: We performed a prospective cohort study in a group of pregnant women infected with human immunodeficiency virus and evaluated the rate of transmission of this virus to the neonate on the basis of the mode of delivery. One group of patients was delivered by means of a "bloodless cesarean section," in which the baby was delivered and not exposed to any maternal blood or bodily fluid. The control group gave birth either by vaginal delivery or by routine cesarean section. All of the newborns were followed up for a minimum of 15 months or until negative findings were confirmed. Multiple antenatal, intrapartum, and postdelivery variables were collected and analyzed.
Results: A total of 108 patients were included in this study and 14 neonates became infected with human immunodeficiency virus (13%). Three of 53 infants delivered by a bloodless cesarean section (5.7%) became infected compared with 11 of 55 control patients (20.0%). This was significant at P = .02 and represented an absolute difference in percentage between the 2 groups of 14.3%, which corresponds to a 71.5% relative reduction in transmission risk (z = 2.27, P = .012). Since the use of zidovudine greatly influences the perinatal transmission rate of human immunodeficiency virus, the study data were reanalyzed with the exclusion of patients who used antenatal or intrapartum zidovudine. Two of 32 infants in the bloodless cesarean section group (6.3%) were infected compared with 9 of 38 in the control group (23.7%). This was significant at P = .04 and revealed an absolute difference in percentage of 17.4%, which corresponds to a 73.4% relative reduction in transmission risk (z = 2.15, P = .016). There was no difference in the transmission rate between the bloodless cesarean section patients who did not use zidovudine (2/32, 6.3%) and the patients who did use zidovudine from the entire study population (3/38, 7.9%).
Conclusion: In the absence of zidovudine usage, these data show that 70% to 75% of the perinatal transmission of human immunodeficiency virus to a newborn occurs from exposure to maternal blood and bodily fluids at the time of birth. This information is important for patients unable to take zidovudine or other antiretroviral agents, but more important, it introduces the concept of other treatment options for the future.