Objective: We performed a meta-analysis to evaluate bacterial vaginosis as a risk factor for preterm delivery.
Study design: Selection criteria were (1). the data appeared in original, published English-language reports of prospective studies or control groups of clinical trials that included women at <37 weeks of gestation with intact amniotic membranes, (2). all the women had to have been screened for bacterial vaginosis that was diagnosed by either clinical criteria or criteria that were based on Gram stain findings, and (3). the outcomes were preterm delivery, spontaneous abortion, maternal or neonatal infection, and perinatal death.
Results: Eighteen studies with results for 20,232 patients were included. Bacterial vaginosis increased the risk of preterm delivery >2-fold (odds ratio, 2.19; 95% CI, 1.54-3.12). Higher risks were calculated for subgroups of studies that screened for bacterial vaginosis at <16 weeks of gestation (odds ratio, 7.55; 95% CI, 1.80-31.65) or at <20 weeks of gestation (odds ratio, 4.20; 95% CI, 2.11-8.39). Bacterial vaginosis also significantly increased the risk of spontaneous abortion (odds ratio, 9.91; 95% CI, 1.99-49.34) and maternal infection (odds ratio, 2.53; 95% CI, 1.26-5.08). No significant results were calculated for the outcome of neonatal infection or perinatal death.
Conclusion: Bacterial vaginosis, early in pregnancy, is a strong risk factor for preterm delivery and spontaneous abortion.