Risk Factors for Preterm Birth Among HIV-Infected Pregnant Ugandan Women Randomized to Lopinavir/Ritonavir- or Efavirenz-Based Antiretroviral Therapy

Background: Protease inhibitor-based antiretroviral therapy (ART) has been associated with preterm birth in some studies. We examined risk factors for preterm birth among women randomized to lopinavir/ritonavir (LPV/r)- or efavirenz (EFV)-based ART. Methods: This was a planned secondary analysis of the PROMOTE-Pregnant Women and Infants Study, an open-label, randomized controlled trial comparing the risk of placental malaria among HIV-infected, ART-naive pregnant Ugandan women assigned to initiate LPV/r- or EFV-based ART at 12-28 weeks gestation. Gestational age was determined based on last menstrual period and ultrasound biometry. All women received bednets and trimethoprim-sulfamethoxazole. Stillbirths, spontaneous abortions, and multiple gestations were excluded from the primary analysis. Potential risk factors for preterm birth (, 37 weeks gestation) were evaluated by univariate and multivariate logistic regression. Results: Three hundred fifty-six women were included in this analysis. At enrollment, median gestational age was 21 weeks and median CD4 cell count was 368 cells per cubic millimeter. 14.7% of deliveries in the EFV arm and 16.2% in the LPV/r arm were preterm. Preterm birth was associated with gestational weight gain below 0.1 kg/week versus 0.1 kg/week or more [odds ratio (OR) = 2.49; 95% confidence interval (CI): 1.38 to 4.47; P = 0.003]. Neither ART regimen of LPV/r versus EFV (OR = 1.12; 95% CI: 0.63 to 2.00; P = 0.69) nor placental malaria (OR = 0.74; 95% CI: 0.38 to 1.44; P = 0.37) was associated with preterm birth. Conclusions: LPV/r was not associated with an increased risk of preterm birth compared with EFV. However, interventions are needed to address modifiable risk factors for preterm birth, such as nutritional status (ClinicalTrials. gov, NCT00993031).