Perinatal outcomes associated with maternal HIV and antiretroviral therapy in pregnancies with accurate gestational age in South Africa.

Objective: To assess the association of maternal HIV infection and antiretroviral therapy (ART) with perinatal outcomes among women with accurate pregnancy dating and birth weights.

Design: Prospective pregnancy cohort study in Soweto, South Africa.

Methods: Gestational age was estimated by first-trimester ultrasound and birth weight was measured in a standardized manner within 24 h of birth. The primary composite outcome 'adverse perinatal outcome' included preterm birth, low birth weight, small for gestational age, stillbirth and neonatal death (NND). Specific adverse perinatal outcomes were secondary outcomes. Logistic regression models adjusted for multiple confounders.

Results: Of 633 women included in the analysis, 229 (36.2%) were HIV positive and 404 (63.8%) HIV negative. Among 125 HIV-positive women who provided detailed information on HIV and ART, 96.7% had clinical stage 1 of HIV disease and 98.4% were on ART during pregnancy, mostly WHO-recommended efavirenz-based ART. Among 109 HIV-positive women with information on timing of ART initiation, 38 (34.9%) initiated ART preconception and 71 (65.1%) antenatally. No newborns were HIV positive. In univariable analysis, maternal HIV infection was associated with increased risk of the composite 'adverse perinatal outcome' [odds ratio (OR) 1.44; 95% confidence interval (CI) 1.03, 2.03], NND (OR 6.15; 95% CI 1.27, 29.88) and small for gestational age (OR 1.55; 95% CI 1.01, 2.37). After adjusting for confounders, maternal HIV infection remained associated with 'adverse perinatal outcome' (adjusted OR 1.47; 95% CI 1.01, 2.14) and NND (adjusted OR 7.82; 95% CI 1.32, 46.42). No associations with timing of ART initiation were observed.

Conclusion: Despite high ART coverage, good maternal health and very low vertical HIV transmission rate, maternal HIV infection remained associated with increased risk of adverse perinatal outcomes. Larger studies using first trimester ultrasound for pregnancy dating are needed to further assess associations with specific adverse perinatal outcomes.