HIV and Syphilis Coinfection in Pregnancy and Adverse Birth Outcomes in Uganda

Abstract

Background: Despite increasing global syphilis incidence, little is known about the combined impact of maternal HIV and syphilis coinfection. We evaluated effects of HIV/syphilis coinfection in pregnancy on birth outcomes. Methods: We conducted 2 prospective birth cohort studies in Uganda from 2017 to 2023. Our primary outcome was birthweight. Our secondary outcome was a composite adverse birth outcome (birthweight<2.5kg stillbirth, early neonatal death, or 5-min APGAR<7). We compared outcomes by HIV and Treponema pallidum particle agglutination assay (TPPA) seropositivity and fitted multivariable regression models. Results: Treponema pallidum particle agglutination assay seroprevalence was 12% (118/967); 19% (94/483) among WHIV and 5% (24/484) among women without HIV. Only 48% of TPPA-seropositive women reported syphilis testing during antenatal care. Stillbirth and early neonatal death were higher among TPPA seropositive (12%, 15/118) than seronegative (4%, 32/849) participants. Low birthweight was associated with HIV seropositivity (−0.1 kg, 95% CI −0.15, −0.04), younger maternal age (0.01 kg per year, 95% CI 0.01, 0.02), and lower gestational age (0.07 kg per week, 95% CI 0.06, 0.09) but not TPPA serostatus. The composite outcome was associated with lower maternal and gestational age. Conclusions: We report high TPPA seroprevalence, low syphilis testing rates, and associations with adverse birth outcomes, emphasizing the need to improve prenatal syphilis testing and treatment.