Abnormal vaginal flora in the first trimester, but not full-blown bacterial vaginosis, is associated with preterm birth

Objective To investigate whether there is a correlation between vaginal flo ra at early gestation and premature delivery and low birth weight. Methods The study group comprised 197 consecutive women who attended routin e prenatal care in Flanders, Belgium, during the first trimester (less than or equal to 14 weeks) and whose pregnancy continued beyond 20 weeks of pre gnancy. Vaginal microbiological flora were studied by microscopy of wet mou nt or Pap smear. Bacterial vaginosis was assessed either clinically (Amsell ), microscopically (clue cells) or by culture of bacterial vaginosis-associ ated bacteria. Results The presence of an intermediate form of vaginal flora disturbance a t the first prenatal visit, rather than full-blown bacterial vaginosis, was associated with low birth weight and preterm birth (relative risk 4.3; 95% confidence interval 1.6-11.4; p = 0.006). The clinical signs and symptoms, as well as the results of vaginal bacterial culture in women with this int ermediate flora differed entirely from those found in women with bacterial vaginosis. Conclusion Disturbed vaginal flora and signs of vaginitis at early gestatio n are associated with preterm birth, but full-blown anaerobic bacterial vag inosis is not. Clinical assessment of the vaginal flora, combined with micr oscopy, was superior to culture results. It could be of importance in futur e studies to rethink the classification of the different types of abnormal vaginal flora.