February 22, 2008
Bacterial vaginosis (BV) is the name of a condition in women where the normal balance of bacteria in the vagina is disrupted and replaced by an overgrowth of certain bacteria. It is sometimes accompanied by discharge, odor, pain, itching, or burning.
Bacterial vaginosis (BV) is the most common vaginal infection in women of childbearing age. In the United States, BV is common in pregnant women.
The cause of BV is not fully understood. BV 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 an increase in harmful bacteria.
Not much is known about how women get BV. There are many unanswered questions about the role that harmful bacteria play in causing BV. Any woman can get BV. However, some activities or behaviors can upset the normal balance of bacteria in the vagina and put women at increased risk including:
It is not clear what role sexual activity plays in the development of BV. Women do not get BV from toilet seats, bedding, swimming pools, or from touching objects around them. Women who have never had sexual intercourse may also be affected.
Women with BV may have an abnormal vaginal discharge with an unpleasant odor. Some women report a strong fish-like odor, especially after intercourse. Discharge, if present, is usually white or gray; it can be thin. Women with BV may also have burning during urination or itching around the outside of the vagina, or both. However, most women with BV report no signs or symptoms at all.
In most cases, BV causes no complications. But there are some serious risks from BV including:
Pregnant women with BV more often have babies who are born premature or with low birth weight (low birth weight is less than 5.5 pounds).
The bacteria that cause BV can sometimes infect the uterus (womb) and fallopian tubes (tubes that carry eggs from the ovaries to the uterus). This type of infection is called pelvic inflammatory disease (PID). PID can cause infertility or damage the fallopian tubes enough to increase the future risk of ectopic pregnancy and infertility. Ectopic pregnancy is a life-threatening condition in which a fertilized egg grows outside the uterus, usually in a fallopian tube which can rupture.
A health care provider must examine the vagina for signs of BV and perform laboratory tests on a sample of vaginal fluid to look for bacteria associated with BV.
Although BV will sometimes clear up without treatment, all women with symptoms of BV should be treated to avoid complications. Male partners generally do not need to be treated. However, BV may spread between female sex partners.
Treatment is especially important for pregnant women. All pregnant women who have ever had a premature delivery or low birth weight baby should be considered for a BV examination, regardless of symptoms, and should be treated if they have BV. All pregnant women who have symptoms of BV should be checked and treated.
Some physicians recommend that all women undergoing a hysterectomy or abortion be treated for BV prior to the procedure, regardless of symptoms, to reduce their risk of developing an infection.
BV is treatable with antibiotics prescribed by a health care provider. Two different antibiotics are recommended as treatment for BV: metronidazole or clindamycin. Either can be used with non-pregnant or pregnant women, but the recommended dosages differ. Women with BV who are HIV-positive should receive the same treatment as those who are HIV-negative.
BV can recur after treatment.
BV is not completely understood by scientists, and the best ways to prevent it are unknown. However, it is known that BV is associated with having a new sex partner or having multiple sex partners.
The following basic prevention steps can help reduce the risk of upsetting the natural balance of bacteria in the vagina and developing BV:
Order Publication Online at www.cdc.gov/std/pub
American Social Health Association (ASHA)
Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines, 2006. MMWR 2006: 55 (No. RR-11)
Hillier S and Holmes K. Bacterial vaginosis. In: K. Holmes, P. Sparling, P. Mardh et al (eds). Sexually Transmitted Diseases, 3rd Edition. New York: McGraw-Hill, 1999, 563-586.
This article was provided by U.S. Centers for Disease Control and Prevention. Visit the CDC's website to find out more about their activities, publications and services.