The prevalence of bacterial vaginosis in pregnant women during early third trimester and the pregnancy complications

Objectives: To investigate the prevalence of bacterial vaginosis (BV) in asymptomatic pregnant women during early-third trimester and to compare the pregnancy complications between pregnant women with and without BV. Materials and Methods: A total of 270 asymptomatic pregnant women at GA 28-32 weeks without history of preterm birth (PB) or cervical surgery were screened for BV, along with other vaginal infections, using gram stain. Nugent criteria was used to categorize vaginal smears into no BV (score 0-3), intermediate flora (IF, score 4-6) and BV (score 7-10). Fifteen weeks later, their medical records were reviewed. Outcomes of interest were premature rupture of membranes (PROM), preterm birth <37 weeks (PB) and birth weight <2,500 grams (LBW). Results: From 270 participants, 233 who delivered at Siriraj hospital were eligible for the study. The prevalence of BV, vaginal candidiasis (VC) and IF were 19.3%, 21% and 36.5%, respectively. None had trichomoniasis or gonococcal infection. One of BV cases had chorioamnionitis and none of all participants had post-partum infection. Multivariate analysis showed the increasing trend of pregnancy complications: PROM (IF 1.6, 95% CI 0.6-4.5; BV 2.2, 95% CI 0.8-6.2, p= 0.339), PB (IF 1.3, 95% CI 0.3-5.1; BV 2.3, 95% CI 0.6-9.4, p= 0.489) and LBW (IF 1.4, 95% CI 0.5-4.1; BV 1.5, 95% CI 0.5-4.9, p= 0.761). Conclusion: BV during GA28-32 weeks in asymptomatic Thai pregnant women was prevalent at 19.3% and tended to increase in pregnancy complications, including premature rupture of membranes, preterm birth and low birth weight.