Bacterial vaginosis is the most common cause of abnormal vaginal
discharge in women of childbearing age, with a prevalence as high as
50% in some communities. The symptoms of discharge and offensive
smell can cause considerable distress, although 50% of women are
asymptomatic when the condition is diagnosed. Microbiologically the
usually dominant lactobacillus flora is overwhelmed by an overgrowth
of predominantly anaerobic organisms, accompanied by a rise in pH. A
biofilm containing predominantly Gardnerella vaginalis and Atopobium
vaginae has been described recently. Metronidazole is the antibiotic of
choice for treatment, but relapse within 1 or 2 months is common. Bacterial
vaginosis is a risk factor for acquisition of sexually transmitted infections
including HIV, and for post-abortion endometritis and adverse
pregnancy outcomes such as late miscarriage and preterm birth. Studies
of antibiotics in pregnancy have not consistently shown reduced adverse
outcomes so better strategies are needed to improve pregnancy outcome.