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

1. 

   View larger version:

   • In this window
   • In a new window

   Figure 1. Analytic framework and key questions.

   KQ = key question.
2. 

   View larger version:

   • In this window
   • In a new window

   Figure 2. Search and selection of literature for all key questions.

   BV = bacterial vaginosis; RCT = randomized, controlled trial. *Cochrane databases include the Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects. †Other sources include reference lists and expert suggestions. ‡We included 7 additional studies for key question 2 and 2 for key question 3 from the 2001 report in the summary of this evidence.
3. 

   View larger version:

   • In this window
   • In a new window

   Figure 3. Study characteristics and absolute risk reduction of delivery before 37 weeks.

   Span = treatment timing spans less than 20 weeks and greater than 20 weeks. *Baseline risk is the percentage of deliveries before 37 weeks in the placebo group. Absolute risk reduction is the difference in probability of delivery before 37 weeks (control minus treatment). †McDonald et al. (58) and Carey et al. (57) performed a high-risk group subanalysis; high-risk group is included in total study population of the average-risk target group. Odendaal et al. (50) included 2 target populations; high-risk and low-risk groups are 2 separate groups.
4. 

   View larger version:

   • In this window
   • In a new window

   Figure 4. Absolute risk reduction of delivery before 34 weeks and before 32 weeks.

   PTD = preterm delivery. *McDonald et al. (58) and Carey et al. (57) performed a high-risk group subanalysis; high-risk group is included in total study population of the average-risk target group. Odendaal et al. (50) included 2 target populations; high-risk and low-risk groups are 2 separate groups.
5. 

   View larger version:

   • In this window
   • In a new window

   Figure 5. Absolute risk reduction of low birthweight and preterm, premature rupture of membranes (PPROM).

   *McDonald et al. (58) and Carey et al. (57) performed a high-risk group subanalysis; high-risk group is included in total study population of the average-risk target group.
6. 

   View larger version:

   • In this window
   • In a new window

   Appendix Figure. Illustration of calculation in Table 2, using the outcome of delivery before 34 weeks in the more selective high-risk group.

   BV = bacterial vaginosis; PTD = preterm delivery. *To calculate the confidence limits for the increase or decrease in adverse outcome, plug in the confidence limits of effect size here. †A negative sign (−) indicates a net increase in adverse outcomes (harm), and a positive sign (+) indicates a net decrease in adverse outcomes (benefit).