Gestational bleeding, bacterial vaginosis, and common reproductive tract infections: risk for preterm birth and benefit of treatment.

Abstract

To examine associations between bacterial vaginosis and other prevalent lower genital tract infections and clinically recognized first-trimester bleeding; possible independent and joint effects of gestational bleeding and bacterial vaginosis or other prevalent infections on preterm birth and premature rupture of membranes; and effects of antimicrobial treatment on reducing risks of preterm birth among these women. A secondary analysis was conducted of 1100 pregnant women enrolled in a prospective observational study that examined the effects of standardized diagnosis and treatment of lower genital tract infections to prevent preterm birth. Sixty percent of women with first-trimester bleeding had one or more study infections detected at the initial examination. First-trimester bleeding was associated independently with the presence of bacterial vaginosis (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.0, 2.3), Trichomonas vaginalis (OR 2.3, 95% CI 1.3, 4.2), and Chlamydia trachomatis (OR 2.7, 95% CI 1.4, 5.1). Preterm birth was increased among women with first-trimester bleeding and bacterial vaginosis (relative risk [RR] 4.4, 95% CI 2.0, 9.5) and bacterial vaginosis and T vaginalis (RR 3.0, 95% CI 1.0, 8.8). Systemic antimicrobial treatment reduced the rate of preterm birth among women with bacterial vaginosis without first-trimester bleeding (RR 0.37, 95% CI 0.16, 0.88). Treatment of women with both first-trimester bleeding and bacterial vaginosis reduced preterm birth (RR 0.52, 95% CI 0.18, 1.55), but not significantly. First-trimester bleeding was increased among women with bacterial vaginosis, T vaginalis, C trachomatis, and combinations of these infections. Women with bacterial vaginosis who also experienced first-trimester bleeding were at heightened risk for preterm birth. Treatment of studied infections reduced significantly the risks of preterm birth among women without first-trimester bleeding.