Treatment of Bacterial Vaginosis in Early Pregnancy and its Effect on
Spontaneous Preterm Delivery and Preterm Premature Rupture of Membranes

Background: This study was conducted to investigate whether screening and treatment of bacterial vaginosis (BV) in early pregnancy reduces the risk of spontaneous preterm delivery or preterm premature rupture of membranes (PPROMs).

Material and methods: Women were screened for BV during their first visit to the maternal health care unit. After the vaginal samples were air dried, they were sent to the gynecological department and were analyzed using Hay/ Ison modified classification. Eligible women were those who lived in Skaraborg County and delivered at Skaraborgs Hospital in Skövde, Sweden. The women were divided into two groups, namely, screened women (with BV or with lactobacilli flora) and unscreened women. Women with BV were offered treatment with vaginal clindamycin.

Results: During 2007-2015, 22,084 deliveries occurred at Skaraborgs Hospital; a total of 6,899 women were screened for BV, out of which 746 (10.8%) had BV flora. Survival analysis showed that women with BV had spontaneous preterm delivery significantly earlier than those with normal lactobacilli flora, even after treatment with vaginal clindamycin (log rank p=0.01). During the same period, 15,189 deliveries occurred at Skaraborgs Hospital; they were not screened for BV. The survival analysis showed that the unscreened women delivered slightly earlier than the screened women (t-test p<0.05), with mean delivery days of 239.4-241.7.

Conclusion: Even though patients with BV had been treated with clindamycin, they still suffered from an increased risk of spontaneous preterm delivery as compared to women with normal lactobacilli flora. The difference between the screened women and the unscreened women could be attributed to the positive effect of the treatment of BV with clindamycin if it can be assumed that there is the same amount of untreated BV in the unscreened group.