Bacterial vaginosis is the name of a vaginal inflammation caused by an overgrowth of bacteria in a woman's vagina. The inflammation sets in when the overgrowth upsets the normal balance of vaginal bacteria. While women who are in their reproductive years are more likely to get bacterial vaginosis, this is a condition any woman can experience. What Cases This Inflammation to Occur? The unfortunate truth is medical experts and researchers have yet to determine exactly what causes a woman to develop bacterial vaginosis.