OBJECTIVES

Bacterial vaginosis (BV) is the most common lower genital tract syndrome among women of reproductive age. This report will be used by the United States Preventive Services Task Force (USPSTF) to update its 2001 recommendation on screening and treatment for bacterial vaginosis in pregnancy. This update report will focus on three critical key questions related to screening, treatment, and adverse effects of screening and/or treatment on pregnancy outcomes in women asymptomatic for bacterial vaginosis at low, average, and high risk for preterm delivery. The previous review and recommendations can be downloaded at http://www.ahrq.gov/clinic/uspstf/uspsbvag.htm.

DATA SOURCES

Searches were conducted in the Cochrane Central Database of Controlled Trials, the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effects through the second quarter of 2006. We also searched Ovid MEDLINE and the Ovid MEDLINE Database of In-Process and Other Non-Indexed Citations from January 2000 to July 2006.

REVIEW METHODS

All captured citations and retrieved papers were independently rated for inclusion in the study by two reviewers, using established inclusion/exclusion criteria related to three critical key questions. Studies of screening or treatment included randomized controlled trials that evaluated screening and/or treatment pregnancy outcomes and/or adverse effects for asymptomatic women with bacterial vaginosis (BV). Participants included pregnant women at low, average, or high risk for preterm delivery. Eligible studies were available in the English language. Studies were also sought by reference lists of related reviews, studies, editorials, reports, websites, and by consulting experts. The USPSTF quality rating system and the Jadad scale (RCTs) were used to rate study quality.

DATA SYNTHESIS AND ANALYSIS

Data on study characteristics, treatment variables, and adverse pregnancy outcomes were abstracted. For each study, we calculated the absolute risk reduction (ARR), and analysis was stratified by risk group (low, average, or high risk). When data allowed, we performed a series of meta-analyses (using new and 2001 report data) to estimate the pooled effect of treatment on preterm delivery (<37 weeks, <34 weeks, or <32 weeks), on low birth weight (LBW), and on preterm premature rupture of membranes (PPROM).

SCREENING RESULTS

No studies comparing a screened population with a non-screened population were found.

TREATMENT RESULTS

Seven new randomized controlled trials were found in the area of treatment of asymptomatic pregnant women with BV since the previous report was published in 2001. Meta-analysis of trials showed no treatment effects at any risk level for preterm delivery for preterm delivery (PTD) <37 weeks, PTD < 34 weeks, PTD < 32 weeks, PPROM, or LBW (<2500g). We did not pool the PTD < 37 weeks, LBW, or PPROM outcome data from high-risk patients due to significant heterogeneity among the trials and inconsistency in the direction of treatment effect. For PTD <37 weeks, three of the five trials reported a significant treatment benefit, while one showed significant treatment harm, and the other showed no benefit.

CONCLUSION

We found no evidence to support screening or treating low-risk pregnant women asymptomatic for BV. Similarly, we found no benefit to screening for and treating BV in the general population of pregnant women who are asymptomatic for BV. (This finding confirms results of the prior review.) Studies of screening and treating women at high risk for preterm delivery conflict on the degree of benefit.

FUTURE RESEARCH

Future studies are needed to prospectively evaluate the benefit of screening and treating asymptomatic BV in women at highest risk for PTD (that is,, greater than a 3-fold increased risk). Conducting such studies well requires standardization of screening timing, treatment regimen (drug, dose, frequency) and detailed measures and reporting of risk factors and outcomes.