Bacterial Vaginosis

What is bacterial vaginosis?

Bacterial vaginosis (BV) is a common inflammation of the vagina caused by bacteria.

How does it occur?

Bacterial vaginosis appears to be caused by an overgrowth of several types of bacteria. It is normal to have these bacteria in the vagina, where they commonly live in small numbers. Sometimes, there are too many bacteria in the vagina. This can cause unpleasant symptoms.

It is not known what causes this overgrowth of bacteria. Most cases of BV occur in sexually active women. Women who have more than one sexual partner have a greater risk of developing the problem. However, women who are not sexually active can also have BV.

Douching or using an IUD for birth control may increase your risk of getting BV.

What are the symptoms?

As many as 50% of women do not have any symptoms. When they do, the most common symptom is a discharge from the vagina. The discharge may be gray or yellowish. It often has an unpleasant odor. For example, it may smell fishy. You may also have itching around the opening of the vagina.

The bacteria associated with BV are sometimes found in the tips of men's penises. However, men do not usually have any symptoms.

How is it diagnosed?

Your healthcare provider will give you a pelvic exam and get a sample of vaginal discharge. The discharge is usually examined under a microscope. The acid content of the discharge, known as the pH, may also be checked. Vaginal discharge from women with BV usually has a particular pattern of pH and appearance. Other lab tests of the discharge may be done to help diagnose BV.

How is it treated?

Bacterial vaginosis that is causing symptoms should be treated. The symptoms of discharge or itching may be uncomfortable, and any discharge odor may be unpleasant. Your healthcare provider may prescribe a medicine called metronidazole (Flagyl) that you take by mouth. Or your provider may prescribe a medicine for you to put into your vagina.

If there is a possibility that you may be pregnant, tell your healthcare provider. Do NOT take metronidazole if you may be pregnant without discussing it first with your healthcare provider. Metronidazole should not be used during the first 3 months of pregnancy. It can be used AFTER the first 3 months of pregnancy if it is clearly needed.

How long will the effects last?

The symptoms usually go away within a few days after you start treatment.

BV increases your risk of becoming infected with HIV if you are exposed to the AIDS virus. Treatment of BV decreases this risk. In addition, if you also have a sexually transmitted infection, such as chlamydia, the risk that the infection will spread into the uterus is higher when you have BV.

If you are pregnant, significant BV overgrowth may increase the chances of having a pregnancy complication such as preterm birth.

How can I take care of myself?

If you are taking metronidazole, do not drink any alcohol until 2 days after you finish the medicine. Drinking alcohol while you are taking metronidazole may cause severe nausea and vomiting.

You should avoid sexual intercourse during treatment of BV. If you do have sexual intercourse while you are taking the medicine, make sure you use a latex or polyurethane condom so you do not become reinfected.

Call your healthcare provider during office hours if:

  • Your symptoms get worse or last more than 1 week. Return to your healthcare provider's office to determine whether you need additional treatment.
  • You have other questions or concerns.

How can I help prevent bacterial vaginosis?

BV is not completely understood by scientists, and the best ways to prevent it are not known. However, your chances of having BV are greater when you have a new sex partner or more than one partner. It is seldom found in women who have never had intercourse.

To help reduce the risk of upsetting the natural balance of bacteria in the vagina and developing BV:

  • Avoid sexual intercourse. If you are sexually active, have just 1 partner who has no other partners.
  • Do not douche.
Developed by David W. Kaplan, MD, and RelayHealth.
Published by RelayHealth.
Last modified: 2009-01-26
Last reviewed: 2008-10-28
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2009 RelayHealth and/or its affiliates. All Rights Reserved.