Bacterial vaginosis (BV) is the most common vaginal infection in women of childbearing age. Although the cause of BV is not fully understood, it is associated with an imbalance in the bacteria that are normally found in a woman's vagina. The vagina normally contains mostly "good" bacteria, and fewer "harmful" bacteria. BV develops when there is a change in the environment of the vagina that causes an increase in harmful bacteria. Not much is known about how women get BV. However, women who have a new sex partner or who have had multiple sex partners are more likely to develop BV, whereas women who have never had sexual intercourse are rarely affected.
Women with BV often have an abnormal vaginal discharge with an unpleasant odor. Some women report a strong fish-like odor, especially after intercourse. The discharge is usually white or gray; it can be thin. Women with BV may also experience burning during urination, itching around the outside of the vagina, or both. Other women with BV report no symptoms at all. In most cases BV causes no complications, but there are some serious risks from BV. For example, pregnant women with BV have a higher rate of preterm delivery and low birth weight infants. In addition, BV has been associated with the development of pelvic inflammatory disease (PID) and increased susceptibility to HIV and other STDs.
BV is treatable with either metronidazole or clindamycin. Treatment is especially important for pregnant women. Male partners generally do not need to be treated, but BV may spread between female sex partners. Bacterial Vaginosis Fact Sheet (CDC)