USPSTF: Avoid screening asymptomatic pregnant women for bacterial vaginosis

The U.S. Preventive Services Task Force recommended against screening for bacterial vaginosis in asymptomatic pregnant women who are not at increased risk for preterm delivery. The task force also said there is insufficient evidence to assess the balance of benefits and harms of screening for bacterial vaginosis in asymptomatic pregnant women who are at increased risk for preterm delivery.

“Accuracy of screening tests for bacterial vaginosis varies,” Leila C. Kahwati, MD, MPH, a senior research scientist at RTI International, and colleagues wrote in JAMA.

“The evidence suggests no difference in the incidence of preterm delivery and related outcomes from treatment for asymptomatic bacterial vaginosis in a general obstetric population but was inconclusive for women with a prior preterm delivery. Maternal adverse events from treatment appear to be infrequent and minor, but the evidence about harms from in utero exposure was inconclusive,” they continued.

Douglas K. Owens, MD, MS, USPSTF chair and general internist at the Veterans Affairs Palo Alto Health Care System, wrote on behalf of the USPSTF in a separate JAMA article that most organizations — including the CDC, the American College of Obstetricians and Gynecologists and the American Academy of Family Physicians — do not recommend screening for bacterial vaginosis in asymptomatic pregnant women. The USPSTF has also previously recommended against it.

In a related editorial, Amanda L. Lewis, PhD, an associate professor at the Center for Women's Infectious Disease Research at Washington University School of Medicine in Saint Louis, and Louise C. Laurent, MD, PhD, director of perinatal research in the department of obstetrics, gynecology and reproductive science at the University of California, San Diego, explained that strategies to prevent preterm birth through antibiotic treatment of bacterial vaginosis “are limited by a poor understanding of what bacterial vaginosis is and how it is mechanistically linked to preterm birth.”

The “gold standard Nugent scoring system” — used in numerous studies to diagnose bacterial vaginosis, has “significant interobserver variability,” they said.

“In a study including 13 experienced researchers, there was full agreement in diagnosis for only 63% of cases,” Lewis and Laurent added.

Although molecular diagnostic tests for bacterial vaginosis have been developed, “the lack of concordance in the targeted bacteria among these tests highlights the fact that it remains unknown which of the bacteria associated with preterm birth are potentially pathogenic and which are innocuous bystanders,” they said.

They said future studies should pinpoint which women are eligible for bacterial vaginosis treatment based on symptoms or risk profiles. – by Janel Miller

References:

Kahwati LC, et al. JAMA. 2020;doi:10.1001/jama.2020.0233.

Lewis AL, Laurent LC. JAMA. 2020;323(13):1253-1255.

US Preventive Services Task Force. JAMA. 2020;doi:10.1001/jama.2020.2684.

Disclosures: Kahwati reports no relevant financial disclosures. Please see the evidence report, recommendation statement and editorial for all other authors’ relevant financial disclosures.