Comparative Safety of Dolutegravir-Based and Second-line Antiretroviral Therapy on Adverse Birth Outcomes: A Retrospective Cohort Study of HIV-Positive Women in Nigeria

Background The combined antiretroviral therapy (cART) has shown to reduce mother child transmission of HIV. This necessitates robust evidence on the comparative safety of different regimens on birth outcomes. There is paucity of evidence on specific cART regimens and adverse birth outcomes in the Nigerian context. Methods A retrospective cohort study was conducted among 420 HIV-positive pregnant women who received antenatal and delivery care at the State Specialist Hospital in Gombe State, Nigeria, between 2018 and 2023. Participants were categorized based on their antenatal cART regimen: first-line (Dolutegravir-based regimen) or second-line (Atazanavir-based regimen). The primary outcomes were fetal death, low birth weight (LBW), preterm birth, and stillbirth. Risk differences were calculated, and multivariate logistic regression was used to identify predictors of adverse outcomes. Results The analysis revealed regimen-specific risks. Exposure to first-line cART was associated with a significantly higher risk of fetal death (Risk Difference [RD] = 0.48, 95% CI: 0.44–0.52) and preterm birth (RD = 0.48, 95% CI: 0.43–0.52). In contrast, exposure to second-line cART was associated with a higher risk of low birth weight (RD = 0.40, 95% CI: 0.39–0.52). The risk of stillbirth was marginally elevated with second-line cART (RD = 0.48, 95% CI: 0.43–0.54). Crucially, an unsuppressed maternal viral load (> 1000 copies/mL) was the strongest independent predictor of adverse outcomes (adjusted Odds Ratio [aOR] = 31.22; 95% CI: 10.29–94.72). Conclusion This real-world study found differential risks of adverse birth outcomes associated with first-line and second-line cART regimens among Nigerian women. However, the most critical modifiable risk factor was unsuppressed viral load during pregnancy. These findings underscore the paramount importance of achieving viral suppression for optimizing birth outcomes and suggest that regimen choice should be carefully considered alongside maternal virological status.