Bacterial vaginosis in pregnancy and the risk of prematurity: a meta-analysis

We conducted this meta-analysis to determine the magnitude of risk conferred by bacterial vaginosis during pregnancy on preterm delivery. We selected articles from a combination of the results of a MEDLINE search (1966-1996), a manual search of bibliographies, and contact with leading researchers. We included case control and cohort studies evaluating the risk of preterm delivery, low birth weight, preterm premature rupture of membranes, or preterm labor for pregnant women who had bacterial vaginosis and those who did not. DATA COLLECTION AND ANALYSIS. Two investigators independently conducted literature searches, applied inclusion criteria, performed data extraction, and critically appraised included studies. Summary estimates of risk were calculated as odds ratios (ORs) using the fixed and random effects models. We included 19 studies in the final analysis. Bacterial vaginosis during pregnancy was associated with a statistically significant increased risk for all outcomes evaluated. In the subanalyses for preterm delivery, bacterial vaginosis remained a significant risk factor. Pooling adjusted ORs yielded a 60% increased risk of preterm delivery given the presence of bacterial vaginosis. Bacterial vaginosis is an important risk factor for prematurity and pregnancy morbidity. Further studies will help clarify the benefits of treating bacterial vaginosis and the potential role of screening during pregnancy.