Two STI screenings in pregnancy cut preterm birth from 18.8% to 14.5% in a South African trial

Repeated screening of pregnant women for sexually transmitted infections (STIs), together with treatment, was associated with fewer preterm births. This is reported by "Nauka w Polsce" with reference to the journal Clinical Infectious Diseases. The randomized clinical trial was carried out by researchers from the University of Pennsylvania and the University of Southern California (USA) scienceinpoland.plNauka w Polscescienceinpoland.plOpen source ↗.

The study covered 2,247 pregnant women attending four public health facilities in South Africa. Women were randomly assigned to one of three groups. The first was screened and treated at the first prenatal visit, with a test of cure three weeks later for those with a detected infection. The second was screened and treated at the first visit and again between weeks 30 and 34 of pregnancy. The third received standard care, with treatment only after symptoms appeared.

Infections and baseline findings

The trial focused on three common curable STIs: chlamydia, gonorrhea and trichomoniasis. These infections are linked to preterm birth and low birth weight, but it had been unclear whether routine screening and treatment in pregnancy improve perinatal outcomes. At baseline, about 27% of participants tested positive for at least one of the three infections, and about 80% of these infections were asymptomatic. Among women rescreened in the third trimester, 9.2% tested positive. Some infections persisted or returned, while others were detected for the first time in women who had tested negative earlier.

Preterm birth and limitations

Preterm birth occurred in 14.5% of women screened twice, compared with 18.8% in the standard-care group, a 23% relative reduction. In the single-screening group the rate was 18.9%, almost identical to standard care. Twice-repeated screening did not significantly reduce low birth weight when that outcome was analyzed separately, so the authors note that the effect on preterm birth requires further study scienceinpoland.plNauka w Polscescienceinpoland.plOpen source ↗.

Co-author Andrew Medina-Marino of the Perelman School of Medicine said the results do not settle how often pregnant patients should be screened; the next step is to determine when screening is most beneficial and for whom. Participants entered the study at a mean of 13 weeks of pregnancy, and the optimal timing remains unclear.

The authors listed limitations. The study was conducted at one location in South Africa with a high STI prevalence, which may limit generalizability. The design also did not allow determining whether specific patient subgroups benefit.