Prevalence of and risk factors for abnormal vaginal flora and its association with adverse pregnancy outcomes in a rural district in north-east Bangladesh

Introduction: The role of screening and treatment for abnormal vaginal flora (AVF) on adverse pregnancy outcomes remains unclear. Using data from women who participated in a population-based cluster randomized trial who were screened and treated for AVF, we report risk factors for AVF and association of persistent AVF with adverse perinatal outcomes. Material and methods: Pregnant women (n = 4221) <19 weeks of gestation provided self-administered mid-vaginal swabs; smears were Nugent-scored. AVF was treated with oral clindamycin; if AVF was present 3 weeks after treatment, persistent AVF was re-treated. We examined risk factors for AVF and the association of persistent AVF with adverse pregnancy outcomes. Results: The prevalence of AVF was 16.5%: 9.8% of women had bacterial vaginosis and 6.8% had intermediate flora. Lower economic and educational status of women were associated with increased risk of AVF. One-third of women with AVF had persistent abnormal flora; these women had a higher risk of a composite measure of adverse pregnancy outcomes from 20 to <37 weeks (preterm live birth, preterm still birth, late miscarriage) (relative risk [RR] 1.33, 95% confidence interval [CI] 1.07-1.65) and of late miscarriage alone (RR 4.15, 95% CI 2.12-8.12) compared to women without AVF. Conclusions: In this study in Sylhet District, Bangladesh, rates of AVF and persistent AVF were high and persistent AVF was associated with adverse pregnancy outcomes, with an especially high associated risk for late miscarriage. Further characterization of the microbiome and relative bacterial species density associated with persistent AVF is needed.