Accuracy of Screening for Bacterial Vaginosis Varies

Leila Kahwati, MD, MPH

Finding ways to identify and treat bacterial vaginosis could reduce its occurrence, according to investigators.

Leila Kahwati, MD, MPH, and a team of investigators updated the evidence on screening and treatment of asymptomatic bacterial vaginosis in pregnancy for the US Preventive Services Task Force. The team found that accuracy of screening tests for bacterial vaginosis varied and evidence suggested no difference in the incidence of preterm delivery and related outcomes for treatment of the condition in a general obstetric population.

Kahwati, and the team developed 5 key questions:

1. Does screening for bacterial vaginosis in asymptomatic pregnant adolescents and women reduce preterm delivery and related morbidity and mortality?
2. What is the diagnostic accuracy of tests used to screen for bacterial vaginosis?
3. What are the harms of screening for bacterial vaginosis in asymptomatic pregnant adolescents and women?
4. Does treatment of bacterial vaginosis during pregnancy reduce preterm delivery and related morbidity and mortality?
5. What are the harms of treatment of bacterial vaginosis in pregnant adolescents and women?

The team used PubMed, the Cochrane Library, and EMASE for English-language articles published from January 1, 2006-May 29, 2016. Two investigators reviewed titles, abstracts, and full-text articles using inclusion criteria for each key question.

For questions 1, 3, and 4, the team included randomized clinical trials and relevant systematic reviews of randomized controlled trials conducted in pregnant women or adolescents. For question 2, studies were included if they reported on diagnostic test accuracy for Amsel clinical criteria or laboratory-based tests in commercial use or feasible for use in primary care settings. Studies included for question 5 reported on outcomes related to fetal exposure to metronidazole or clindamycin.

The investigators collected relevant study characteristics and data for eligible outcomes from each included study.

Overall, Kahwati and the team included 44 studies from 48 publications. Among those included, 25 of test accuracy (question 2), 13 evaluating the benefits of treatment for preterm delivery and related pregnancy outcomes (question 4), and 14 evaluating the harms of treatment were identified (question 5).

Across the accuracy studies, sensitivity ranged from .36-1 and specificity ranged from .49-1. There was no significant association between treatment and spontaneous delivery before 37 weeks (pooled ARD, -1.44; 95% CI, -3.31 to .43; 8 randomized controlled trials, n=7571) or any delivery before 37 weeks (pooled ARD, .2; 95% CI, -1.13 to 1.53; 6 randomized controlled trials, n=6307).

Findings were inconsistent among the 5 trials reporting findings among women with a prior preterm delivery—3 showed significant beneficial effect, 2 did not.

There were infrequent and minor maternal adverse events, though such events were slightly more common with active treatment compared with placebo across 8 randomized controlled trials. What’s more, two analyses of studies reported no significant association between metronidazole exposure and congenital malformations (OR, .96; 95% CI, .75-1.22; OR, 1.08; 95% CI, .9-1.29).

All in all, the report found that accuracy of screening tests for bacterial vaginosis varied.

The report, “Screening for Bacterial Vaginosis in Pregnant Adolescents and Women to Prevent Preterm Delivery,” was published online in JAMA Network Open.