Studies of antiretroviral therapy (ART) use during pregnancy in HIV-infected women have suggested that ART exposure may be associated with adverse birth outcomes. However, there are few data from sub-Saharan Africa where HIV is most common, and few studies involving the World Health Organization’s (WHO’s) recommended first-line regimens.

We enrolled consecutive HIV-infected pregnant women and a comparator cohort of uninfected women at a primary-level antenatal care facility in Cape Town, South Africa. Gestational assessment combined clinical history, examination and ultrasonography; outcomes included preterm (PTD), low birthweight (LBW) and small for gestational age (SGA) deliveries. In analysis we compared birth outcomes between HIV-infected and -uninfected women, and HIV-infected women who initiated ART before vs during pregnancy.

In 1554 women (mean age 29 years) with live singleton births at time of analysis, 82% were HIV-infected, 92% of whom received a first-line regimen of tenofovir, emtricitabine and efavirenz. Overall, higher levels of PTD [22% vs 13%; odds ratio (OR) 1.94, 95% confidence interval (CI): 1.34, 2.82] and LBW (14% vs 9%; OR 1.62, 95% CI: 1.05, 2.29) were observed in HIV-infected vs uninfected women, although SGA deliveries were similar (9% vs 11%; OR 1.06, 95% CI: 0.71, 1.61). Adjusting for demographic characteristics and HIV disease measures, HIV-infected (vs HIV-uninfected) women had persistently increased odds of PTD [adjusted odds ratio (AOR) 2.03; CI 1.33, 3.10]; associations with LBW were attenuated (AOR 1.47; CI 0.90, 2.40). Among all HIV-infected women, there appeared to be no association between the timing of ART initiation (before or during pregnancy) and adverse birth outcomes.

These findings suggest that current WHO-recommended ART regimens appear relatively safe in pregnancy, although more data are required to understand the aetiology of preterm delivery in HIV-infected women using ART.