Evidence on the Benefits and Harms of Screening and Treating Pregnant Women Who Are Asymptomatic for Bacterial Vaginosis: An Update Review for the U.S. Preventive Services Task Force

5 February 2008 | Volume 148 Issue 3 | Pages 220-233

Background: Bacterial vaginosis is the most common lower genital tract syndrome among women of reproductive age. There has been continued debate about the value of screening and treating asymptomatic pregnant women for bacterial vaginosis.

Purpose: To examine new evidence on the benefits and harms of screening and treating bacterial vaginosis in asymptomatic pregnant women.

Data Sources: English-language studies on Ovid MEDLINE (2000 to September 2007) and Cochrane Library databases (through September 2007), reference lists, and expert suggestions.

Study Selection: Screening, treatment, or adverse effect studies with pregnancy outcome data in women who are asymptomatic for bacterial vaginosis.

Data Extraction: Study and patient characteristics, treatment variables, adverse pregnancy outcomes, and internal validity quality criteria from the U.S. Preventive Services Task Force (USPSTF) and Jadad scale were abstracted.

Data Synthesis: 7 new randomized, controlled treatment trials and 2001 report data were combined in a series of meta-analyses to estimate the pooled effect of treatment on preterm delivery (<37, <34, and <32 weeks); low birthweight; and preterm, premature rupture of membranes.

Limitations: No screening studies that compared a screened population with a nonscreened population were found. Significant heterogeneity was found among the high-risk treatment trials (P < 0.001). It is not clear from the detailed description of the studies which factors explain the differences in preterm delivery rates and potentially the association of treatment effect; however, both raise concern for the unintended potential for harm.

Conclusion: No benefit was found in treating women with low- or average-risk pregnancies for asymptomatic bacterial vaginosis. More research is needed to better understand these groups and the conditions under which treatment can be harmful or helpful, and to explore the relevance of bacterial vaginosis to other adverse pregnancy outcomes, such as delivery before 34 weeks.

Author and Article Information

From the Oregon Evidence-based Practice Center and Oregon Health & Science University, Portland, Oregon, and the U.S. Department of Health and Human Services, Bethesda, Maryland.

Acknowledgment: The authors thank Andrew Hamilton, MLS, MS, for conducting the literature searches, and USPSTF leads Kimberly Gregory, MD, MPH, Lucy Marion, PhD, RN, and Diana Petitti, MD, MPH, and AHRQ officers Iris Mabry, MD, MPH and Mary Barton, MD, MPP, for their guidance on this project.

Grant Support: This report was conducted by the Oregon Evidence-based Practice Center under contract to the Agency for Healthcare Research and Quality, Rockville, MD, according to Contract #290-02-0024, Task Order Number 2 for the USPSTF.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Peggy Nygren, MA, Oregon Health & Science University, Mail Code BICC, 3181 SW Sam Jackson Park Road, Portland, OR 97239; e-mail, nygrenp{at}ohsu.edu.

Current Author Addresses: Ms. Nygren, Drs. Fu and Guise, Ms. Freeman, and Ms. Bougatsos: Oregon Health & Science University, 3181 SW Sam Jackson Road, Portland, OR 97239.

Dr. Klebanoff: National Institute of Child Health and Human Development, National Institutes of Health, 6100 Executive Boulevard, Room 7B05F, MSC 7510, Bethesda, MD 20892.