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Bacterial vaginosis

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Bacterial vaginosis

Bacterial vaginosis (BV) is an infection in the vagina. BV is caused by changes in the amount of certain types of bacteria in your vagina. BV is common, and any woman can get it. BV is easily treatable with medicine from your doctor or nurse. If left untreated, it can raise your risk for sexually transmitted infections (STIs) and cause problems during pregnancy.  

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What is bacterial vaginosis (BV)?

Bacterial vaginosis (BV) is an infection in the vagina. BV is caused by changes in the amount of certain types of bacteria in your vagina. BV can develop when your vagina has more harmful bacteria than good bacteria.

Who gets BV?

BV is the most common vaginal infection in women ages 15 to 44.1 But women of any age can get it, even if they have never had sex.

You may be more at risk for BV if you:

  • Have a new sex partner
  • Have multiple sex partners
  • Douche 2
  • Do not use condoms or dental dams
  • Are pregnant. BV is common during pregnancy. About 1 in 4 pregnant women get BV.3 The risk for BV is higher for pregnant women because of the hormonal changes that happen during pregnancy.
  • Are African-American. BV is twice as common in African-American women as in white women.4
  • Have an intrauterine device (IUD), especially if you also have irregular bleeding5

How do you get BV?

Researchers are still studying how women get BV. You can get BV without having sex, but BV can also be caused by vaginal, oral, or anal sex. You can get BV from male or female partners.  

What are the signs and symptoms of BV?

Many women have no signs or symptoms. If you do have signs or symptoms, they may include:

  • Unusual vaginal discharge. The discharge can be white (milky) or gray. It may also be foamy or watery. Some women report a strong fish-like odor, especially after sex.
  • Burning when urinating
  • Itching around the outside of the vagina
  • Vaginal irritation

These symptoms may be similar to vaginal yeast infections and other health problems. Only your doctor or nurse can tell you for sure whether you have BV.

What is the difference between BV and a vaginal yeast infection?

BV and vaginal yeast infections are both common causes of vaginal discharge. They have similar symptoms, so it can be hard to know if you have BV or a yeast infection. Only your doctor or nurse can tell you for sure if you have BV.

With BV, your discharge may be white or gray but may also have a fishy smell. Discharge from a yeast infection may also be white or gray but may look like cottage cheese.

How is BV diagnosed?

There are tests to find out if you have BV. Your doctor or nurse takes a sample of vaginal discharge. Your doctor or nurse may then look at the sample under a microscope, use an in-office test, or send it to a lab to check for harmful bacteria. Your doctor or nurse may also see signs of BV during an exam.

Before you see a doctor or nurse for a test:

  • Don't douche or use vaginal deodorant sprays. They might cover odors that can help your doctor diagnose BV. They can also irritate your vagina.
  • Make an appointment for a day when you do not have your period.

How is BV treated?

BV is treated with antibiotics prescribed by your doctor.

If you get BV, your male sex partner won't need to be treated. But, BV can be spread to female partners. If your current partner is female, she needs to see her doctor. She may also need treatment.

It is also possible to get BV again. Learn how to lower your risk for BV.

BV and vaginal yeast infections are treated differently. BV is treated with antibiotics prescribed by your doctor. Yeast infections can be treated with over-the-counter medicines. But you cannot treat BV with over-the-counter yeast infection medicine.

What can happen if BV is not treated?

If BV is untreated, possible problems may include:6

  • Higher risk of getting STIs, including HIV. Having BV can raise your risk of getting HIV, genital herpes, chlamydia, pelvic inflammatory disease, and gonorrhea. Women with HIV who get BV are also more likely to pass HIV to a male sexual partner.
  • Pregnancy problems. BV can lead to premature birth or a low-birth-weight baby (smaller than 5 1/2 pounds at birth). All pregnant women with symptoms of BV should be tested and treated if they have it.

What should I do if I have BV?

BV is easy to treat. If you think you have BV:

  • See a doctor or nurse. Antibiotics will treat BV.
  • Take all of your medicine. Even if symptoms go away, you need to finish all of the antibiotic.
  • Tell your sex partner(s) if she is female so she can be treated.
  • Avoid sexual contact until you finish your treatment.
  • See your doctor or nurse again if you have symptoms that don't go away within a few days after finishing the antibiotic.

Is it safe to treat pregnant women who have BV?

Yes. The medicine used to treat BV is safe for pregnant women. All pregnant women with symptoms of BV should be tested and treated if they have it.

If you do have BV, you can be treated safely at any stage of your pregnancy. You will get the same antibiotic given to women who are not pregnant.

How can I lower my risk of BV?

Steps you can take to lower your risk of BV include:

  • Help keep your vaginal bacteria balanced. Use warm water only to clean the outside of your vagina. You do not need to use soap. Even mild soap can cause infection or irritate your vagina. Always wipe front to back from your vagina to your anus. Keep the area cool by wearing cotton or cotton-lined underpants.
  • Do not douche. Douching removes some of the normal bacteria in the vagina that protect you from infection. This may raise your risk of BV. It may also make it easier to get BV again after treatment. Doctors do not recommend douching.
  • Practice safe sex. The best way to prevent the spread of BV through sex is to not have vaginal, oral, or anal sex. If you do have sex, you can lower your risk of getting BV, and any STI, with the following steps. The steps work best when used together. No single step can protect you from BV or every single type of STI. Steps to lower your risk of BV or STIs include:
    • Use condoms. Condoms are the best way to prevent BV or STIs when you have sex. Make sure to put on the condom before the penis touches the vagina, mouth, or anus. Other methods of birth control, like birth control pills, shots, implants, or diaphragms, will not protect you from STIs.
    • Get tested. Be sure you and your partner are tested for STIs. Talk to each other about your test results before you have sex.
    • Be monogamous. Having sex with just one partner can lower your risk for BV or STIs. Be faithful to each other. That means that you only have sex with each other and no one else.
    • Limit your number of sex partners. Your risk of getting BV and STIs goes up with the number of partners you have.
    • Don't abuse alcohol or drugs, which are linked to sexual risk-taking. Drinking too much alcohol or using drugs also puts you at risk of sexual assault and possible exposure to STIs.

How can I protect myself if my female partner has BV?

If your partner has BV, you can lower your risk by using protection during sex.

  • Use a dental dam every time you have sex. A dental dam is a thin piece of latex that is placed over the vagina before oral sex.
  • Cover sex toys with condoms before use. Remove the condom and replace it with a new one before sharing the toy with your partner.

More information about BV

For more information about bacterial vaginosis, call the OWH Helpline at 800-994-9662, or contact the following organizations:


  1. Centers for Disease Control and Prevention. (2014). Bacterial Vaginosis.
  2. Klebanoff, M.A., et al. (2010). Personal Hygienic Behaviors and Bacterial Vaginosis. Sex Transm Dis; 37(2):94-9.
  3. Koumans, E.H., Sternberg, M., Bruce, C., McQuillan, G., Kendrick, J., Sutton, M., Markowitz, L. (2007). The Prevalence of Bacterial Vaginosis in the United States, 2001-2004; Associations with Symptoms, Sexual Behaviors, and Reproductive Health. Sexually Transmitted Diseases; 34(11): 864-869.
  4. Ness, R.B., et al. (2003). Can known risk factors explain racial differences in the occurrence of bacterial vaginosis? J Natl Med Assoc; 95:201–212.
  5. Madden, T. et al. (2012). Risk of bacterial vaginosis in users of the intrauterine device: a longitudinal study. Sex Transm Dis; 39(3): 217-222.
  6. Centers for Disease Control and Prevention. (2010). Sexually Transmitted Diseases Treatment Guidelines, 2010. MMWR; 59 (No. RR-12).

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All material contained on this page is free of copyright restrictions and may be copied, reproduced, or duplicated without permission of the Office on Women's Health in the Department of Health and Human Services. Citation of the source is appreciated.

This fact sheet was reviewed by Centers for Disease Control and Prevention (CDC) staff.

Content last updated: May 26, 2015.

Content last reviewed: November 19, 2014.

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