Antenatal and perinatal strategies to prevent mother-to-child transmission of HIV infection.

Mother-to-child transmission (MTCT) is the dominant mode of acquisition of HIV infection for children. Each day an estimated 1600 children born to HIV-infected mothers become infected, 1500 of whom are in sub-Saharan Africa. Mother-to-child transmission can occur before, during and after delivery; overall rates of MTCT range from 15 to 35%. Risk factors for MTCT include maternal viral load levels, vaginal delivery, prematurity and breastfeeding. Approaches to reduce the risk of MTCT include reduction of maternal viral load through antiretroviral prophylaxis, avoidance of exposure through birth canal cleansing or elective caesarean section delivery and refraining from breastfeeding, and boosting the host immune system through nutritional supplementation or immunization. Substantial reductions in the risk of MTCT can be achieved with antiretroviral prophylaxis during pregnancy, delivery and in the neonatal period, both in settings with and without breastfeeding. Elective caesarean section independently decreases the risk, but is not a safe and feasible option in most high prevalence areas. Birth canal cleansing with chlorhexidine does not reduce the rate overall, but may be beneficial in a subgroup of women with prolonged duration of ruptured membranes. Micronutrient supplementation, including vitamin A, does not reduce MTCT of HIV, but may improve pregnancy outcome generally.