Screening for and Treatment of Bacterial Vaginosis Reduced Preterm Delivery in High-Risk Pregnant Women: A Systematic Review and Meta-Analysis

Introduction: Bacterial vaginosis (BV) is a risk factor for preterm delivery. Yet, previous studies have found BV treatment ineffective in preventing preterm delivery in unselected population. This study aimed to evaluate the effectiveness of BV screening and treatment in reducing the rate of preterm deliveries before 37 weeks in high-risk women. Materials and Methods: Embase, PubMed, Ovid- Medline, and Web of Science were searched. Randomized controlled trials that evaluated antibiotic treatment for BV versus no treatment/placebo were included. The primary outcome was the rate of preterm delivery and/or late miscarriages in pregnant women with a history of preterm delivery. The pooled relative risks (with 95% CI) were estimated. The Cochrane's Q test of heterogeneity, and I2 were used to assess heterogeneity. In total, 4,701 papers were retrieved of which seven met inclusion criteria and were analyzed. Results: Among the participating women, 738 were at high risk for preterm delivery and included in the analysis. Among them, 397 and 341 women received active or placebo treatment, respectively. The included studies had a low risk of bias. In six out of seven studies, the risk factor for preterm delivery was a previous preterm delivery. One study (N = 16) was excluded from the analysis since no group had preterm deliveries. Treatment for BV in high-risk women reduced the rate of preterm deliveries (pooled relative risk with 95% CI, 0.65 [0.44-0.98]). The protective effect of BV treatment was statistically significant in women treated with clindamycin, and when treatment was started after 20 gestational weeks. Conclusion: Screening for and treatment of BV may be effective in preventing preterm delivery in high-risk pregnant women. Randomized clinical trials are needed to confirm the findings of this study.