Seroprevalence of HIV infection in pregnancy is on the increase worldwide. Approximately 10 million infants will have been infected by the year 2000 and the majority of these children will have acquired infection by vertical transmission of HIV from infected mothers. Recent reports suggested that pregnancy does not accelerate the course of HIV infection. Prospective studies from industrialized countries where most women have asymptomatic HIV infection, have not shown an association with increased risk of adverse pregnancy outcome. Estimates of the rate of vertical transmission range from 15% to 40%.