Bacterial vaginosis, vaginal fluid neutrophil defensins, and preterm birth

To examine the association between bacterial vaginosis, vaginal fluid neutrophil defensins, and preterm birth.

Vaginal fluid specimens were obtained at 24-29 weeks' gestation from 242 cases with preterm birth and 507 noncases sampled using a case-cohort study design. We tested for bacterial vaginosis by Gram staining and Nugent scores and assayed for neutrophil defensins by enzyme-linked immunosorbent assay. Bacterial vaginosis was studied as a categoric variable (negative, intermediate, and positive), whereas defensins were studied as a continuous, categoric (based on percentiles), and dichotomous measure (presence versus absence). Three gestational age cut points were used to define preterm birth. Modified Cox proportional hazard models were used to evaluate the associations between bacterial vaginosis, defensins, and degree (less than 32, less than 34, and less than 37 weeks) and type (premature rupture of membranes, preterm labor) of preterm birth.

Elevated vaginal fluid neutrophil defensins were not associated with birth before 37 weeks. Compared with women who did not have measurable vaginal fluid defensins, women with higher defensin levels (0-2.8 micro g/mL, 2.8-8.2 micro g/mL, and greater than 8.2 micro g/mL) had a greater risk of delivering before 32 weeks. Hazard ratios adjusted for maternal race and vaginal bleeding during pregnancy and 95% confidence intervals for these defensin levels were 1.7 (0.4, 6.9), 2.4 (0.7, 7.9), and 3.1 (1.0, 9.8), respectively. Bacterial vaginosis status did not influence the association between defensins and preterm birth.

Elevated concentrations of vaginal fluid neutrophil defensins at 24-29 weeks' gestation might predict preterm birth before 32 weeks.