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Bacterial Vaginosis

What is bacterial vaginosis?

Bacterial vaginosis (BV) is a common vaginal condition.  It is thought to be caused by an overgrowth of a bacterium called gardnerella vaginalis and certain other bacteria often found in the vaginal fluid.

What are the symptoms?

Symptoms may include:

  • An increased amount of vaginal discharge, usually thin and watery, and white or grayish in color.
  • Discharge with a foul, unpleasant odor.  The odor is often stronger after sexual intercourse. 
  • Mild vaginal itching or irritation due to increased moisture accumulating in the genitals. 

These symptoms may be similar to a yeast or a Trichomonas infection.  As the symptoms may be mild or intermittent, many women will have the condition for weeks or months before seeking advice.  Bacterial vaginosis does not cause pelvic pain, unusual bleeding, or fever.

college.jpgHow is it diagnosed?

The diagnosis is made in the clinic on the basis of the appearance and microscopic examination of the vaginal discharge.  

How is it treated?

Usually only women with symptoms require treatment.  Sometimes it resolves spontaneously.  When treatment is indicated, the most effective treatment is the antimicrobial drug metronidazole, taken orally (in pill form) or insert vaginally (through a suppository) , or clindamycin.  Don't drink alcoholic beverages while taking metronidazole as even small amounts of alcohol may cause abdominal distress, nausea, vomiting, flushing or headaches. Loose clothing, cotton underwear and good hygiene help reduce the irritating moisture.  Even with effective treatment, recurrences are common. 

What are the consequences of untreated BV?

In the woman who is not pregnant, there is no evidence that BV is harmful in any way.  However, if a pregnant woman has untreated BV, her risk of delivering a premature, low birth weight infant increases by 40%.  If a woman with BV chooses to have an abortion, her BV should be treated prior to the procedure, or she will be at risk of developing pelvic inflammatory disease (PID) after the abortion.

How does it develop?

There are a number of theories but this can't be answered for certain right now.  Many women (one study showed 40 - 50%) normally carry these bacteria in the vagina in small numbers without any problems. Under certain conditions as yet undefined, the organisms multiply and then cause the annoying discharge and odor.  At this time, there is no evidence that the condition is sexually transmitted.  Males do not get symptoms.  Studies show that treatment of male partners has no effect on treatment outcome for the female.

Additional resources

The Center for Disease Control's information on BV

The American Council of Obstetricians and Gynecologists' FAQ on vaginitis, which can be caused by BV

If you have any questions and are a UW student or established Hall Health patient, you may call one of our Consulting Nurses for further information.


Authored by: Hall Health Center Women's Health Clinic staff

Reviewed by: Hall Health Center Women's Health Clinic staff, January 2014