Vaginal clindamycin in preventing preterm birth and peripartal infections in asymptomatic women with bacterial vaginosis: a randomized, controlled trial.

OBJECTIVE: To determine whether treatment of bacterial vaginosis (BV) in early pregnancy decreases the risk of preterm delivery and peripartum infectious morbidity. METHODS: In this multicenter, randomized, double-masked, placebo-controlled intervention trial, screening for BV was performed by vaginal Gram stain obtained from 5432 healthy women with singleton pregnancies during the first antenatal clinic visit at 10--17 weeks' gestation. Bacterial vaginosis-positive women with no past history of preterm delivery were randomized to a single course of treatment with either 2% vaginal clindamycin cream or identical placebo cream for 7 days. Repeat Gram stains were taken 1 week after treatment and at 30--36 weeks' gestation. Preterm delivery was defined as spontaneous delivery before 37 gestational weeks. Peripartum infectious morbidity was defined as postpartum endometritis, postpartum sepsis, postcesarean wound infection, or episiotomy wound infection, necessitating antimicrobial therapy. According to the power analysis, 180 patients were needed for both treatment arms to show a three-fold difference in the rates of preterm births. RESULTS: The overall prevalence of BV was 10.4%. Of all BV-positive women, 375 (66%) were randomized to the treatment arms. The primary cure rate was 66% in the clindamycin group; in the placebo group, 34% spontaneously cleared BV (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.3, 2.8). The rate of preterm deliveries was 5% in the clindamycin group and 4% in the placebo group (OR 1.3, 95% CI 0.5, 3.5). The rate of peripartum infectious morbidity was 11% in the clindamycin group and 18% in the placebo group (OR 1.6, 95% CI 0.9, 2.8). Bacterial vaginosis recurred in 7% of women. The rate of preterm deliveries was 15% in this subgroup compared with 2% among women who remained BV negative (OR 9.3, 95% CI 1.6, 53.5). CONCLUSION: Vaginal clindamycin did not decrease the rate of preterm deliveries or peripartum infections, but recurrent or persistent BV increased the risk for these complications.