What is bacterial vaginosis?

Bacterial vaginosis (BV) is a vaginal infection linked to an imbalance of good (lactobacilli) and harmful (anaerobes) bacteria that are normally found in the vagina. It is the most common type of vaginal infection in women ages 15 to 44. Although researchers do not know the cause of BV or how some women contract it, it is known that women who are sexually active are at higher risk.

What are the symptoms of bacterial vaginosis?

Many women with BV do not have symptoms. But some include:

  • A thin white or gray vaginal discharge
  • Pain, itching or burning in the vagina
  • A strong fishlike odor, especially after sex
  • Burning when urinating
  • Itching around the outside of the vagina.

Symptoms of BV are similar to vaginal yeast infections, which is why it is important for women to be examined by a doctor to determine whether they’ve contracted BV.

What are the risk factors for bacterial vaginosis?

Several circumstances may lead to BV, including the following:

  • Having multiple sex partners or a new sex partner: Doctors aren’t sure how sex contributes to BV, but findings show that women who have multiple sex partners or new sex partners are more likely to develop the condition. In addition, BV occurs more often in women who have sex with women. However, any women can develop BV.
  • Douching: This method of cleansing the vagina with water or other mixtures of fluids can lead to an overgrowth of harmful bacteria, which may cause bacterial vaginosis. Women who douche are five times more likely to develop BV than women who don’t.
  • Pregnancy: Pregnant women are more likely to get BV because of the hormonal changes that occur during this time.
  • A natural lack of lactobacilli bacteria: According to research, if a woman’s vagina doesn’t provide enough of this good bacteria, they’re more likely to develop bacterial vaginosis.
  • Race: Experts have found that BV is twice as common among African-American women compared with white women.

How is bacterial vaginosis diagnosed?

Doctors will initially ask a woman who may have BV about her medical history to determine whether she has had any previous vaginal or sexually transmitted infections.

A physician may perform a pelvic exam and visually examine the vagina for signs of infection. In addition, a doctor may order tests on samples of vaginal secretions to check for an overgrowth of anaerobic bacteria in a woman’s vaginal flora.

Laboratory tests can also detect signs of bacterial vaginosis. These exams include a vaginal pH test, a wet mount (a sample of vaginal discharge mixed with a salt solution that tests for the presence of certain unusual cells called clue cells), a whiff test (several drops of a potassium hydroxide solution added to a sample of vaginal discharge to see whether a strong fishy smell is created) and oligonucleotide probes (a test that detects the DNA of bacterial vaginosis).

How is bacterial vaginosis treated?

Although BV may resolve without treatment, the infection can also be cured with antibiotics. These oral and vaginal medications include metronidazole, clindamycin and tinidazole.

If left untreated, BV can increase a person’s risk of contracting sexually transmitted infections (STIs), such as chlamydia, gonorrhea and HIV. What’s more, women living with HIV who get BV are more likely to transmit the virus to a sexual partner. BV is also linked to premature births and low-birth-weight babies.

After treatment for BV, it’s common for the infection to recur within three to 12 months. In addition, stopping treatment early may increase the risk of recurrence. Usually, male sexual partners don’t need treatment, but women should get tested and may require medicine.

Last Reviewed: October 30, 2019