Bacterial Vaginosis

Last Reviewed: November 2006

What is bacterial vaginosis?

Bacterial vaginosis (BV) is a common vaginal infection. It affects one of every five women of childbearing age.

What causes BV?

A normal, healthy vagina has mostly healthy or "good" bacteria and very few unhealthy or "bad" bacteria. BV develops when the pH balance or level of acidity in the vagina is upset. This change allows the "bad" bacteria to increase 100 to 1,000 times more than normal. At the same time, the "good" bacteria are destroyed.

Women who are sexually active are much more likely to get BV. But, it is not known if BV is spread through sex. You may have a greater chance of getting BV if you use douches, or if you frequently clean your vagina with soap or other products. Douching and frequent cleaning may rinse away or destroy healthy bacteria and let "bad" bacteria take over.

What are the signs and symptoms?

More than half the women with BV don't know they have it. If symptoms are present, they are usually mild.

Symptoms may include:

  • A thin, gray or white discharge that sticks to the walls of the vagina,
  • An unpleasant, fishy or musty odor,
  • Burning when urinating,
  • Occasional vaginal itching, and
  • Vaginal irritation during or after sex.

Bacterial vaginosis can sometimes lead to pelvic inflammatory disease (PID). PID is when a woman's reproductive system gets infected and may include infection of the uterus, tubes, ovaries, or even inside the lower belly (abdomen).

How will I know if I have BV?

To know for sure, you should visit a health care provider. He or she will give you a pelvic exam and look at your vaginal fluid under a microscope to check the levels of "good" and "bad" bacteria. The pH level of your vagina may also be measured.

When can I have sex again?

If you have been treated for BV you should not have sex for seven days after your treatment is over.

Is there a cure?

Yes. BV can be cured with antibiotics. Your provider will give you either metronidazole (me troe ni' da zole ) or clindamycin (klin da mye' sin). If you are given either medicine as a pill, it is taken by mouth. Either can be used with non-pregnant or pregnant women, but the dosages differ for each. You should not drink alcohol if you are taking metronidazole.

Each medicine is also available as a cream or gel. The creams and gels are used directly in your vagina. It is important to take all of your medicine even if the signs and symptoms go away.

It is even more important that you get treatment if you are pregnant. 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. If you are pregnant, or you think you are pregnant, see your health care provider.

Most of the time, treatment lowers the number of "bad" bacteria in your vagina. But, it will not totally get rid of them. In some women, the bacteria can multiply and cause BV to come back.

What about my partner(s)?

Although it is not known whether BV is spread through sex, your partner( s) should be checked for BV and other sexually transmitted diseases. This is even more important if your BV keeps coming back.

How can I prevent BV?

  • Use a latex or polyurethane condom every time you have sex. This may lower your chances of having this infection again.
  • Limit the number of sexual partners you have.
  • Do not douche or forcefully clean your vagina with soap or other feminine hygiene products. These products might upset your vagina's normal balance of "good" and "bad" bacteria.

To learn more:

If you have more questions about bacterial vaginosis, or you want to know how to find a clinic near you, call your local health department.

You may also call the National STD Hotline at 1-800-CDC-INFO 1-800-232-4636