Antenatal Screening for Sexually Transmitted Infections to Reduce Preterm Birth or Low Birthweight (Philani Ndiphile Study): A Randomized Three-Group Trial

BackgroundChlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis are curable sexually transmitted infections (STIs) associated with adverse birth outcomes. Most infections are asymptomatic. Whether antenatal STI screening improves birth outcomes remains uncertain. MethodsIn a randomized three-group trial in South Africa, pregnant women aged 18 years or older were assigned before 27 weeks gestation to: (1) screening and treatment for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis at enrollment, with tests-of-cure (One-Time Screening); (2) screening and treatment at enrollment, repeated at 30 to 34 weeks (Two-Time Screening); or (3) Standard-of-Care (Syndromic management). The primary outcome was a composite of preterm birth (<37 weeks gestation) or low birthweight (<2500 g), analyzed in the modified intention-to-treat population of participants with live births. Components of the composite outcome were evaluated individually as the main secondary outcomes. The study was registered with ClinicalTrials.gov, NCT04446611. FindingsOf 2247 enrolled participants, 1910 had live births. The composite outcome occurred in 22{middle dot}9% of the One-Time Screening group (risk ratio [RR] 0{middle dot}99; 95% confidence interval [CI] 0{middle dot}81-1{middle dot}21), 20{middle dot}6% of the Two-Time Screening group (RR 0{middle dot}89; 95% CI 0{middle dot}72-1{middle dot}09), compared with 23{middle dot}2% of the Standard-of-Care group. Preterm birth occurred in 18{middle dot}9% of the One-Time Screening group (RR 1{middle dot}00; 95% CI 0{middle dot}80-1{middle dot}26), 14{middle dot}5% of the Two-Time Screening group (RR 0{middle dot}77; 95% CI 0{middle dot}60-0{middle dot}99), and 18{middle dot}8% of the Standard-of-Care group. Low birthweight occurred in 14{middle dot}1% of the One-Time Screening group (RR 1{middle dot}10; 95% CI 0{middle dot}83-1{middle dot}46), 12{middle dot}9% of the Two-Time Screening group (RR 1{middle dot}01; 95% CI 0{middle dot}76-1{middle dot}35), and 12{middle dot}8% of the Standard-of-Care group. InterpretationNeither screening strategy for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis reduced the primary composite outcome of preterm birth or low birthweight, or low birthweight alone. The Two-Time antenatal STI screening strategy, however, reduced preterm birth by 23%.