title: 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.
abstract: 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.
  
  
  OBJECTIVE
  To examine new evidence on the benefits and harms of screening and treating bacterial vaginosis in asymptomatic pregnant women.
  
  
  METHODS
  English-language studies on Ovid MEDLINE (2000 to September 2007) and Cochrane Library databases (through September 2007), reference lists, and expert suggestions.
  
  
  METHODS
  Screening, treatment, or adverse effect studies with pregnancy outcome data in women who are asymptomatic for bacterial vaginosis.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Oregon Evidence-based Practice Center and Oregon Health & Science University, Portland, Oregon 97239, USA. nygrenp@ohsu.edu
authors.forename: Peggy
authors.initials: P
authors.lastname: Nygren
authors.forename: Rongwei
authors.initials: R
authors.lastname: Fu
authors.forename: Michele
authors.initials: M
authors.lastname: Freeman
authors.forename: Christina
authors.initials: C
authors.lastname: Bougatsos
authors.forename: Mark
authors.initials: M
authors.lastname: Klebanoff
authors.forename: Jeanne-Marie
authors.initials: JM
authors.lastname: Guise
mesh_terms: D005260:Female; D006801:Humans; D008403:Mass Screening / Q000009:adverse effects; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000188:drug therapy*; D047928:Premature Birth / Q000517:prevention & control*; D012307:Risk Factors; D016585:Vaginosis, Bacterial / Q000175:diagnosis* / Q000188:drug therapy*