Antenatal Screening for Sexually Transmitted Infections to Reduce Preterm Birth or Low Birthweight (Philani Ndiphile Study): A Randomized 3-Group Trial

BACKGROUND: Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis are predominantly asymptomatic curable sexually transmitted infections (STIs) associated with adverse birth outcomes. Whether antenatal STI screening improves birth outcomes remains uncertain. METHODS: In this randomized trial (NCT04446611), pregnant women ≥18 years were assigned before 27 weeks' gestation to (1) screening and treatment for C. trachomatis, N. gonorrhoeae, and T. vaginalis at enrollment, with tests-of-cure (1-Time Screening); (2) screening and treatment at enrollment, repeated at 30-34 weeks (2-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); each component was evaluated individually as a secondary outcome. RESULTS: Of 2247 enrolled, 1910 had live births. The composite outcome occurred in 22.9% of the 1-Time Screening (RR 0.99; 95% CI .81-1.21) and 20.6% of the 2-Time Screening groups (RR 0.89; 95% CI .72-1.09), compared with 23.2% of the Standard-of-Care group. Preterm birth occurred in 18.9% of the 1-Time Screening group (RR 1.00; 95% CI .80-1.26), 14.5% of the 2-Time Screening group (RR 0.77; 95% CI .60-0.99), and 18.8% of the Standard-of-Care group. Low birthweight occurred in 14.1% of the 1-Time Screening group (RR 1.10; 95% CI .83-1.46), 12.9% of the 2-Time Screening group (RR 1.01; 95% CI .76-1.35), and 12.8% of the Standard-of-Care group. CONCLUSIONS: Neither STI screening strategy reduced the primary composite outcome or low birthweight alone. The 2-Time Screening strategy reduced preterm birth by 23%.