On October 29, 2026, Penn Medicine announced results from a randomized clinical trial in Clinical Infectious Diseases. Screening and treating pregnant patients twice during pregnancy for chlamydia, gonorrhea and trichomoniasis was associated with a 23% lower risk of preterm birth than standard symptom-based care. The Philani Ndiphile study, run by researchers at the University of Pennsylvania and the University of Southern California, enrolled 2,247 pregnant participants at four government clinics in South Africa. They were randomized to one screen at the first prenatal visit (with a test-of-cure three weeks after treatment), screens at the first visit and again at 30–34 weeks, or standard care.

Why It Matters

The finding that most infections had no symptoms, and that one screen wasn't enough, supports **repeat, low-friction testing**. That is the opportunity for at-home and point-of-care STI diagnostics (Everlywell, myLAB Box, rapid NAAT platforms) and for telehealth programs building prenatal panels. It adds to the evidence behind [e-visit STI testing](/stories/kaiser-sti-evisit-testing-study) and the new [chlamydia/gonorrhea treatment options](/stories/zoliflodacin-chlamydia-coinfection-idweek) moving through regulators. The trial was conducted in a high-prevalence setting, so U.S. guideline bodies will want confirmation before changing schedules. But "screen twice" is a simple message that payers and diagnostic companies can act on.

Preterm birth occurred in 14.5% of the twice-screened group compared with 18.8% under standard care. Screening once did not help (18.9%). At enrollment, about 27% of participants had at least one of the three infections, and about 80% of those infections caused no symptoms. In the third-trimester rescreen, 9.2% tested positive, a mix of persistent, recurrent and new infections. The authors say the result needs more study: the two-screen approach did not significantly reduce the trial's primary composite outcome of preterm birth or low birthweight, or low birthweight alone. "The results give us an important signal, but they don't settle the question of how often pregnant patients should be screened," said co-lead author Andrew Medina-Marino, PhD.

Sources

Update — 2026-10-30

Initial entry — story first created.