Spontaneous recovery of bacterial vaginosis during pregnancy is not associated with an improved perinatal outcome

Background. Bacterial vaginosis in pregnant women is an established risk factor for premature labor, rupture of membranes, and preterm delivery, but information on its natural history during pregnancy is limited. Method and material. In this study, 635 pregnant women at less than 35 weeks' gestation were screened for bacterial vaginosis. Results. The prevalence of bacterial vaginosis, as assessed by Gram slain examination of vaginal smears, was 19.7% (125/635). Ninety-two women were retested 4 to 8 weeks later, and bacterial vaginosis persisted in 51.1% (47/92). The incidence of preterm delivery was significantly increased in women with bacterial vaginosis at enrolment (RR 3.1, 95% CI: 1.8-5.4). However, the risk of prematurity was similar in women with or without a persistence of bacterial vaginosis. Conclusion. These results suggest that the diagnosis of bacterial vaginosis at any point during pregnancy is associated with an increased risk of perinatal complications in spite of spontaneous recovery in subsequent examinations.