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

The Philani Ndiphile trial randomized 2,247 pregnant women across four South African clinics to enrollment screening with test-of-cure, enrollment plus third-trimester screening, or syndromic management. Testing targeted chlamydia, gonorrhea, and trichomoniasis. Among 1,910 participants with documented live births, neither screening strategy significantly reduced the primary composite of preterm birth or low birthweight. Repeat screening produced a lower preterm-birth rate, but this secondary result must be weighed against the negative primary endpoint and trial limitations.

Clinical Considerations

• Primary composite: Rates were 22.9% with one-time screening, 20.6% with repeat screening, and 23.2% with standard care; both confidence intervals included no effect.
• Secondary preterm-birth outcome: Repeat screening yielded 14.5% versus 18.8% with standard care (RR 0.77; 95% CI 0.60–0.99); one-time screening showed no benefit.
• Neither strategy reduced low birthweight. Multiple comparisons and a confidence interval close to the null temper interpretation of the preterm-birth finding.
• Funding constraints left the live-birth analysis below its planned sample size. Excluding non-live-birth outcomes also limits assessment of overall pregnancy benefit.
• Prior preterm birth was less common in the repeat-screening group; sensitivity analyses accounting for this imbalance produced comparable findings.
• Third-trimester screening attendance was 68%; partner treatment was not directly provided. High STI/HIV prevalence and the syndromic comparator limit transferability.

Practice Applications

• Interpret repeat screening as a promising secondary finding, not established evidence that this strategy prevents adverse birth outcomes overall.
• Distinguish the trial’s birth-outcome question from the separate clinical rationale for detecting and treating maternal STIs.
• Review applicability against local screening guidance and care pathways; this trial does not independently establish a new universal screening schedule.