A randomised controlled trial of vaginal clindamycin for early pregnancy bacterial vaginosis

Objective To determine whether treatment of bacterial vaginosis (BV) with v aginal clindamycin affects pregnancy outcome. Materials and methods Mothers with singleton pregnancies and without previo us preterm delivery in 17 health centres in Oulu from March 1996 Until Marc h 1998, in whom BV was diagnosed by Gram slain of a vaginal swab at the fir st antenatal visit (at the 12th gestational week) were randomised at Oulu U niversity Hospital to have a one-week. course of vaginal clindamycin, or pl acebo. A follow up sample of Gram slain was taken two weeks after randomisa tion and at the 30th gestational weeks. Pregnancy outcome data was obtained from hospital records. Primary outcome was preterm birth, and puerperal in fectious morbidity the other outcome measure. Results During the study period 1956 women were screened, of whom 143 (7.3% ) were BV- positive. One hundred and one were randomised. The total preterm birth rate of BV+ women randomised was 9.9% (10/101), Preterm birth occurr ed in 20.7% (6/29) vs 0% (0/26) according to whether BV persisted or not (P < 0.01). The preterm birth rate was 13.7% (7/51) in the clindamycin group vs 6.0% (3/50) in the placebo group (OR 2.5, 95% CI 0.6-10). BV was cured j ust after treatment in 17 out of 51 (33%) of the clindamycin- treated patie nts vs 17 out of 50 (34%) of the placebo- treated patients (OR 1.0, 95% CI 0.4-2.2). There was a difference in puerperal infectious morbidity in patie nts where BV persisted (31%, 9/29) compared with those in which BV did not persist (7.7%, 1/26) (OR 5.4, 95% CI 1.04-28). Infections were seen in 4/51 (8%) of the clindamycin treated vs 10/50 (20%) of the placebo treated case s, (OR 0.3, 95% CI 0.1-1.2). Conclusion The prevalence of BV was lower than expected in this low risk po pulation, but nevertheless it increased the risk of preterm birth and puerp eral infectious morbidity, the risk being highest in cases where BV persist ed during pregnancy. Vaginal clindamycin treatment fur BV in the first trim ester of pregnancy did not appear to reduce the risk of preterm birth or pu erperal infections.