Bacterial vaginosis: etiology, association with preterm labor, diagnosis, and management

Bacterial vaginosis is a polymicrobial condition (anaerobes, Gardnerella vaginalis) that is associated with symptomatic vaginal discharge. Bacterial vaginosis can be reliably diagnosed through clinical indicators such as clue cells on wet preparation of vaginal discharge, an increased pH of vaginal discharge, a fishy, amine odor emitted when a sample of vaginal discharge is placed in potassium hydroxide, and cultures that isolate G. vaginalis. The vaginal discharge is often heavy and foul smelling, and usually resolves when treated with metronidazole, 500 mg twice a day for seven days. It is unclear whether bacterial vaginosis is caused by G. vaginalis or whether G. vaginalis is simply associated with the condition and its development is related to other factors. More importantly, the association of bacterial vaginosis with preterm labor (whether merely a risk factor or a causal factor) needs to be clarified, and the question of whether treatment of bacterial vaginosis in pregnancy will improve fetal outcome by decreasing prematurity needs to be addressed.