Screening for bacterial vaginosis in pregnancy

Context: Bacterial vaginosis (BV) is a strong independent risk factor for a dverse pregnancy outcomes. BV is found in 9% to 23% of pregnant women. Symp toms include vaginal discharge, pruritus, or malodor, but often women with BV are asymptomatic. Objectives: To determine whether screening and treating pregnant women for BV reduces adverse pregnancy outcomes, as part of an assessment for the U.S . Preventive Services Task Force. Data Sources: Randomized clinical trials of BV treatment in pregnancy that measured pregnancy outcomes were identified from multiple searches in MEDLI NE from 1966 To 1999, the Cochrane Controlled Trials Register and Library, and national experts. All randomized controlled trials of BV treatment in p regnancy that specifically measured pregnancy outcomes. Data Extraction: The following information was abstracted: study design and blinding, diagnostic methods, antibiotic interventions, timing of antibiot ic treatment in pregnancy, criteria for treatment, comorbidities, demograph ic details, risk factors for preterm delivery such as previous preterm deli very, compliance, rates of spontaneous and total preterm delivery less than 37 weeks and less than 34 weeks, preterm premature rupture of membranes, l ow birth weight less than 2500 grams, spontaneous abortion, postpartum endo metritis, and neonatal sepsis. For each study, we measured the effect of tr eatment by calculating the difference in the rate of a given pregnancy outc ome in the control group minus the treatment group (the absolute risk reduc tion [ARR]). A stepwise procedure based on the profile likelihood was appli ed to assess heterogeneity, to pool studies when appropriate, and to calcul ate the mean and 90% confidence intervals (CIs) for the effect of treatment . Data Synthesis: Seven randomized controlled trials met inclusion criteria f or the meta-analysis. We found no benefit to BV treatment in average-risk w omen for any pregnancy outcome. Results of studies of high-risk populations , women with previous preterm delivery, were statistically heterogeneous. T hey clustered into two groups; one showed no benefit (ARR= -0.08, 90% CI=-0 .19 to 0.04), whereas the three homogeneous studies showed potential benefi t of BV treatment (pooled ARR=0.22; 90% CI=0.13 to 0.31) for preterm delive ry before 37 weeks. Four high-risk studies reported results for preterm del ivery less than 34 weeks. The pooled estimate showed no benefit (ARR=0.04; 90% CI=-0.02 to 0.09), but variation was noted among individual studies. Tw o trials of high-risk women found an increase in preterm delivery less than 34 weeks in women who did not have BV but received BV treatment. Compariso ns of patient populations, treatment regimens, and study designs did not ex plain the heterogeneity among studies. Conclusions: We found no benefit to routine BV screening and treatment. A s ubgroup of high-risk women may benefit from BV screening and treatment; how ever, there may be a subgroup for whom BV treatment could increase the occu rrence of preterm delivery.