Shift in vaginal flora (bacterial vaginosis) and the frequency of chorioamnionitis in a high-risk population

Objective: To test the association between a shift in vaginal flora (SVF) and chorioamnionitis in a population with a high prevalence of both conditions. Study Design: Subjects were women with Pap smears and placentas examined at the Medical Center of Louisiana, New Orleans. The presence of subchorionitis, chorionitis, chorioamnionitis and necrotizing chorioamnionitis was evaluated blindly on placental tissue sections. The presence of SVF was evaluated on matching cervical Pap smears obtained during gestation. Results: Three hundred twenty-two placentas and the corresponding Pap smears were examined. Chorioamnionitis was identified in 112 placentas. It was not significantly associated with maternal age or ethnicity, but its prevalence was inversely related to gestational age. SVF was observed in 114 Pap smears. It was more common among African Americans than other ethnic groups but was not significantly associated with maternal age or gestational age at delivery. SVF was more often observed in Pap smears collected in early pregnancies than in those collected later. There was no significant association between chorioamnionitis and SVF before and after accounting for ethnicity, maternal age, gestational age at Pap smear collection, and interval between Pap smear collection and delivery. Conclusion: SVF had no significant predictive value for chorioamnionitis in our study population.