Objective To explore pregnancy outcome in HIV-1-positive and HIV-negative women, and mother-to-child transmission (MTCT) according to mode of delivery under effective highly active antiretroviral therapy (HAART).Design Cohort of 143 pregnant HIV-1-infected women including a matched case-control study in a 2:1 ratio of controls to cases (n = 98).Setting Academic Medical Center in Amsterdam and Erasmus Medical Center in Rotterdam, the Netherlands.Population Consecutive referred HIV-1 infected pregnant women treated with HAART and matched control not infected pregnant women.Main outcome measures MTCT, preterm delivery, low birthweight, pre-eclampsia.Results MTCT was 0% (95% CI 0-2.1%). Seventy-eight percent of HIV-1-infected women commenced and 62% completed vaginal delivery. The calculated number of caesarean sections needed to prevent a single MTCT was 131 or more. Preterm delivery rates were 18% (95% CI 11-27) in women infected with HIV-1 and 9% (95% CI 5-13) in controls (P = 0.03). HAART used at <13 weeks of gestation was associated with a 44% preterm delivery rate compared with 21% when HAART was started at or after 13 weeks and 14% in controls. (Very) low birthweight and incidence of pre-eclampsia were not different between HIV-1 and controls.Conclusions We have not demonstrated any MTCT after vaginal delivery in women effectively treated by HAART. The HAARTassociated increase in preterm delivery rate is mainly seen after first trimester HAART use.

Nelfinavir- or nevirapine-containing HAART regimens during pregnancy are well tolerated. Side effects of antiretroviral therapy are more frequent in pregnant than in non-pregnant women.