Should we screen for bacterial vaginosis in those at risk for preterm labor?

Bacterial vaginosis (BV) is associated with preterm delivery (strength of recommendation [SOR]: A, meta-analysis). However, treating asymptomatic, low-risk women with BV does not always prevent preterm delivery (SOR: A, randomized controlled trials [RCTs]). There is some benefit to early screening by Gram stain using Nugent's criteria1 (Table ) and treating BV-positive women with a history of preterm delivery, premature rupture of membranes, low birth weight infants, or spontaneous abortion. In this group, treatment has been associated with decreased rates of preterm labor, preterm prelabor rupture of membranes, and low birth weight infants (SOR: B, conflicting RCTs). Empirically treating high-risk women without documented infection has been associated with an increase in preterm deliveries and neonatal infections (SOR: B, single RCT)