Bacterial vaginosis in early pregnancy may predispose for preterm birth and postpartum endometritis

Background. Bacterial vaginosis (BV) has been reported to be associated with spontaneous preterm delivery and infectious morbidity after birth in non-Swedish populations. Our intention was to investigate the situation in a Swedish population. Methods. In this cohort study, 924 patients were enrolled consecutively. A Papanicolaou (Pap) smear, which included a posterior fornix sample, was obtained at the first visit (median: 12 weeks and 1 day) at the two antenatal care units in central Goteborg 1990-91. Clue cells in the Pap smear were considered to be consistent with BV. The principal outcome variables were spontaneous preterm birth (<37 weeks) and postpartum endometritis. A relative risk (RR) was calculated with a 95% confidence interval. Results. The prevalence of BV was 15.6%. An association was seen between BV in early pregnancy and postpartum endometritis [RR 3.26 (1.38-7.71)]. A non-significant association was found between BV and spontaneous preterm birth [RR 2.10 (0.90-4.94)]. A multiple logistic regression analysis was performed adjusting for primi-/multiparity and antibiotics during pregnancy and the odds ratio was 2.16 (0.87-3.64). Conclusions. The prevalence of BV was 15.6% in this Swedish pregnant population. The risk for postpartum endometritis was tripled among women with BV in early pregnancy. The risk for spontaneous preterm birth among women with BV was doubled but non-significant, although the samples were obtained early in pregnancy.