Bacterial vaginosis (BV) is a common infection that can be caused by an imbalance between the “good” and “harmful” bacteria that are normally found in a woman’s vagina. It's the most common type of vaginal infection in women ages 15 to 44.Bacterial vaginosis is surprisingly prevalent among pregnant women: Up to 19 percent of expectant mothers in the United States have BV.

Causes and Risk Factors of Bacterial Vaginosis

BV happens when there’s an imbalance between good (healthy) and bad (disease-causing) bacteria in the vagina.

Gardnerella is the bacteria most often associated with bacterial vaginosis; between the lack of “good” bacteria such as lactobacilli and the overgrowth of Gardnerella or other harmful bacteria, symptoms of BV infection can result. Anything that alters the vagina’s pH balance can alter bacteria levels and set the stage for BV. This means that douching or using vaginal deodorants can lead to BV.
Also, a study in a March 2018 issue of the International Journal of Microbiology found that the prevalence of bacterial vaginosis is higher among women who are daily smokers, drink alcohol daily, or consume a nonvegetarian diet.
A study published in January 2019 in the American Journal of Obstetrics & Gynecology found that women who are overweight or obese have a greater occurrence of BV than lean women do.
Having a new sex partner or multiple partners can increase a woman’s risk of developing bacterial vaginosis.
Indeed, new research suggests that a man’s penile microbiome — the community of bacteria in and around the penis — could predict whether his female partner develops BV.

Duration of Bacterial Vaginosis

Once BV is treated with antibiotics, it usually goes away. But sometimes it persists or recurs, often within three months, for reasons that aren’t entirely understood. If a person keeps getting BV, a longer course of antibiotics may be necessary.

Complications of Bacterial Vaginosis

If left untreated, BV can increase your risk for sexually transmitted infections (STIs) such as herpes, gonorrhea, chlamydia, and HIV.

It also can cause other problems (such as having a low-birth-weight baby or premature rupture of the membranes) during pregnancy.

RELATED: A His-and-Hers Sexual Health Issue

Racial Disparity in Bacterial Vaginosis

Data suggests that African American women experience BV more frequently than women of European ancestry. But the basis for this racial disparity is not understood. Differences in known risk factors, such as a history of smoking, do not explain the racial difference in the occurrence of BV. More research is needed.
According to an analysis of women who participated in the National Health and Nutrition Examination Survey (NHANES) 2001–2004, some nonwhite women have higher rates of BV (African Americans, 51 percent; Mexican Americans, 32 percent) than white women (23 percent).

Resources We Love

To learn more about BV, check out the following websites.

Planned Parenthood

A reliable source of information about reproductive and sexual health and healthcare, Planned Parenthood provides vital facts about women’s health and wellness, sexually transmitted infections, birth control, pregnancy, and more.

American College of Obstetricians and Gynecologists (ACOG)

ACOG is a go-to source for research-supported information about women’s reproductive health issues, including fertility, conception, pregnancy, and best practices for each of these issues.

Editorial Sources and Fact-Checking

  • Bacterial Vaginosis. Centers for Disease Control and Prevention (CDC).
  • Bacterial Vaginosis in Pregnant Persons to Prevent Preterm Delivery: Screening. U.S. Preventive Services Task Force. April 7, 2020.
  • What Is Bacterial Vaginosis? Planned Parenthood.
  • Ramjet E, Raghubanshi B, Maskey S, et al. International Journal of Microbiology. March 2018.
  • Brookheart R, Lewis W, Peipert J, et al. American Journal of Obstetrics & Gynecology. January 2019. 
  • Mehta SD, et al. Frontiers in Cellular and Infection Microbiology. August 4, 2020.
  • Bacterial Vaginosis. U.S. Department of Health and Human Services Office on Women’s Health.
  • Bilardi JE, Walker S, Temple-Smith M, et al. PloS One. September 2013.
  • Bacterial Vaginosis. National Health Service UK.
  • Bacterial Vaginosis. CDC 2015 Sexually Transmitted Diseases Treatment Guidelines.
  • Bradshaw C, Morton A, Hocking J, et al. Journal of Infectious Diseases. June 2006.
  • Faught B, Reyes S. Journal of Women’s Health. September 2019.
  • Koumans EH, Sternberg M, Bruce C, et al. Sexually Transmitted DiseasesNovember 2007.
  • Fettweis J, Brooks J, Serrano M, et al. Microbiology. October 2014. 
  • Bacterial Vaginosis Statistics. CDC.
  • Ness RB, Hillier S, Ritcher S, et al. Journal of the National Medical AssociationApril 2003.


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