The role of bacterial vaginosis in preterm labor and preterm birth: a case-control study.

Objective: To study the association between preterm labor and bacterial vaginosis; in women with preterm labor, to determine whether vaginosis modifies the risk of preterm delivery. Study Design: Case-control study. We used Amsel’s clinical criteria to test 102 patients hospitalized for preterm labor and 102 control patients for bacterial vaginosis. Results: Patients with preterm labor were diagnosed with bacterial vaginosis significantly more often (13.8%, 95% confidence interval (CI) (7.7–22.0) than control patients (0.0%, 95% CI (0.0–3.6)) (P<0.001). Among the former, the time elapsed to delivery was identical regardless of the patient’s bacterial vaginosis status (elapsed time: 35.9 versus 37.1 days, rate of spontaneous preterm birth 42.9 versus 43.2%, not significant). Conclusion: Bacterial vaginosis is associated with preterm labor. Nonetheless, it does not appear to predict preterm birth among these patients.