Background: We evaluated associations between antepartum weight change and adverse pregnancy outcomes and between antiretroviral therapy (ART) regimens and week-50 postpartum body mass index in IMPAACT 2010.

Methods: Women with HIV-1 in 9 countries were randomized 1:1:1 at 14-28 weeks gestational age (GA) to start dolutegravir(DTG)+emtricitabine(FTC)/tenofovir alafenamide fumarate(TAF) versus DTG+FTC/tenofovir disoproxil fumarate(TDF) versus efavirenz (EFV)/FTC/TDF. Insufficient antepartum weight gain was defined using IOM guidelines. Cox-proportional hazards regression models were used to evaluate the association between antepartum weight change and adverse pregnancy outcomes: stillbirth (≥20 weeks GA), preterm delivery (<37 weeks GA), small for gestational age (SGA<10th percentile), and a composite of these endpoints.

Results: 643 participants were randomized: 217 in DTG+FTC/TAF, 215 in DTG+FTC/TDF, and 211 in EFV/FTC/TDF arms. Baseline medians were: GA 21.9 weeks, HIV RNA 903 copies/mL, CD4 count 466 cells/uL. Insufficient weight gain was least frequent with DTG+FTC/TAF (15.0%) versus DTG+FTC/TDF (23.6%) and EFV/FTC/TDF (30.4%). Women in the DTG+FTC/TAF arm had the lowest rate of composite adverse pregnancy outcome. Low antepartum weight gain was associated with higher hazard of composite adverse pregnancy outcome (HR 1.44, 95%CI 1.04, 2.00) and SGA (HR 1.48, 95%CI 0.99, 2.22). More women in the DTG+FTC/TAF arm had body mass index ≥25 kg/m2 at 50 weeks postpartum (54.7%) versus the DTG+FTC/TDF (45.2%) and EFV/FTC/TDF (34.2%) arms.

Conclusions: Antepartum weight gain on DTG regimens was protective against adverse pregnancy outcomes traditionally associated with insufficient weight gain, supportive of guidelines recommending DTG-based ART for women starting ART during pregnancy. Interventions to mitigate postpartum weight gain are needed.

Keywords: HIV; adverse pregnancy outcomes; antepartum weight change; postpartum weight; women's health.