Bacterial Vaginosis.

Bacterial vaginosis, the most prevalent cause of vaginal discharge in the United States, is characterized microbiologically by a shift in the vagina away from a lactobacillus-predominant flora and toward a predominantly anaerobic milieu. The cause of bacterial vaginosis is unknown, but the epidemiology of the syndrome suggests that it is sexually associated. Bacterial vaginosis has been associated with various complications, such as pelvic inflammatory disease, preterm birth, postoperative gynecologic infections, and abnormal Pap smears. Abnormal vaginal flora may also be a biologic risk factor for sexually transmitted diseases, including HIV infection.