Effects of Metronidazole Therapy on Preterm Labor in Women with Bacterial Vaginosis

Regarding to prevalence of preterm labor and its consequences, there are different reports on relationship between bacterial vaginosis and preterm labor. This study was performed to evaluate the effect of metronidazole therapy on preterm labor in women with bacterial vaginosis. This randomized clinical trial was performed on 120 women suffering from bacterial vaginosis at 20-34 weeks of pregnancy, to evaluate the therapeutic effect of metronidazole to delay preterm labor in Shabih Khani maternity hospital in Kashan, Iran in 2002. Bacterial vaginosis was diagnosed based on clinical and laboratory findings. The patients were randomly divided into two groups. The patients in the case group received 500 mg metronidazole BID for 7 consecutive days, but the control group did not receive it. The demographic characteristics of the patients such as, pregnancy age, educational level and job of the spouse were similar at both case and control groups. Double-blind follow up of the patients at the whole stages of parturition and after delivery with respect to the delivery method, infection, and fever was done by other practitioner besides the main researcher. The results were analyzed statistically by chi-square, and Fischer’s exact tests. 420 patients entered the study, of whom 120 (28.6%) had bacterial vaginosis. The antibiotic and control groups were not significantly different for maternal age, job of the spouse, and education. No difference was observed in spontaneous preterm birth before 37 weeks of gestation in antibiotic-treated compared with control group. Treatment with metronidazole in symptomatic women with a bacterial vaginosis in the late second trimester does not decrease the incidence of preterm delivery.