The vaginal microflora and fetal fibronectin in pregnancy

Abstract

Objectives: The aims of this study were to characterize the vaginal microflora and determine fetal fibronectin (fFn) in women during normal pregnancy (Study I) and pregnancies complicated by preterm labor (PTL), preterm premature rupture of the membranes, vaginal bleeding of unknown cause (Study II & III), and prolonged pregnancy (Study IV & V), and to assess possible associations between the microflora and fFn (Study VI). Material and methods: Quantitative aerobic and anaerobic microbiological cultures were performed and vaginal fFn was determined by enzyme immunoassay in samples taken from women with normal and complicated pregnancies.Results: A lactobacilli-dominated flora was found throughout pregnancy in the majority of healthy women. Women lacking hydrogen peroxide(H2O2)-producing lactobacilli were more likely to harbour C. albicans. The presence of H2O2-producing lactobacilli flora decreased the frequency of bacterial vaginosis (BV). In women with threatening preterm delivery (PTD) a lactobacilli-deficient flora was more common than in controls. BV was associated with delivery before 37 weeks. Women delivered < 34 weeks lacked H2O2-producing lactobacilli. Postterm women also had lactobacilli-dominated floras, however, H2O2-producing lactobacilli were less common than in controls. No difference in the vaginal concentration of fFn was found between early, mid and late pregnancy. In women with PTL a positive test (fFn > 0.05 mg/L) predicted delivery < 34 weeks with a sensitivity of 64 % and a specificity of 87 %. The predictive value of a negative test was 92 %. However, in postterm women fFn was a poor predictor of delivery within three days and in predicting dysfunctional labor. BV, Prevotella spp., E. faecalis, and absence of lactobacilli were associated with elevated vaginal fFn.Conclusion: H2O2-producing-lactobacilli in the vaginal fluid decreases the risk for preterm delivery, BV, and colonisation with C. albicans. The vaginal microflora is of significance for fibronectin. Women with PTL and a negative fibronectin are at low risk for PTD.