Bacterial Vaginosis (BV)

Medically Reviewed on 7/11/2023

What is bacterial vaginosis (BV)?

Bacterial vaginosis also is referred to as nonspecific vaginitis, is a vaginal condition that can produce vaginal discharge and results from an overgrowth of certain kinds of bacteria in the vagina. In the past, the condition was called Gardnerella vaginitis, after the bacteria that were thought to cause the condition. However, the newer name, bacterial vaginosis, reflects the fact that several species of bacteria naturally live in the vaginal area and may grow to excess, rather than a true infection with foreign bacteria, such as occurs with many sexually-transmitted diseases (STDs).

The Gardnerella organism is not the sole type of bacteria causing the symptoms. Other kinds of bacteria that can be involved in bacterial vaginosis are Lactobacillus, Bacteroides, Peptostreptococcus, Fusobacterium, Eubacterium, as well as several other types. When these multiple species of bacteria that normally reside in the vagina become unbalanced, a woman can have a vaginal discharge with a foul odor.

How common is bacterial vaginosis?

  • Bacterial vaginosis is a common condition.
  • It is the most common vaginal complaint in women of childbearing age.
  • Studies have shown that approximately 29% of women in the U.S. are affected.
  • Bacterial vaginosis is found in about 25% of pregnant women in the U.S. and approximately 60% of women who have an STD.

Is bacterial vaginosis an STD or yeast infection?

  • Bacterial vaginosis is not the same thing as an STD or yeast infection.
  • Bacterial vaginosis is not dangerous, but it can cause disturbing symptoms.
  • Any woman with an unusual discharge should be evaluated so that more serious infections such as Chlamydia and gonorrhea can be excluded.
  • Symptoms may also mimic those found in yeast infections of the vagina and trichomoniasis (an STD), and these conditions must also be excluded in women with vaginal symptoms.

What are symptoms and signs of bacterial vaginosis (BV)?

Many women with bacterial vaginosis have no signs or symptoms at all. When symptoms do occur, the most common include:

  1. An abnormal amount of vaginal discharge
  2. The vaginal discharge is thin and grayish-white.
  3. Vaginal odor (foul-smelling or unpleasant fishy odor)
  4. The vaginal discharge and odor are often more noticeable after sexual intercourse.
  5. Pain with sexual intercourse or urination (rare symptoms).

Symptoms of bacterial vaginosis, if present, can occur any time in the menstrual cycle, including before, during, or after the menstrual period. The amount of vaginal discharge that is considered normal varies from woman to woman. Therefore, any degree of vaginal discharge that is abnormal for a particular woman should be evaluated.


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What causes bacterial vaginosis (BV)?

Researchers have had difficulty determining exactly what causes bacterial vaginosis. At present, it seems to be that a combination of multiple bacteria must be present together for bacterial vaginosis to develop. Bacterial vaginosis typically features a reduction in the number of the normal hydrogen peroxide-producing lactobacilli in the vagina. Simultaneously, there is an increase in the concentration of other types of bacteria, especially anaerobic bacteria (bacteria that grow in the absence of oxygen). As a result, the diagnosis and treatment are not as simple as identifying and eradicating a single type of bacteria. Why the bacteria combine to cause the unbalance is unknown.

Certain risk factors have been identified that increase the chances of developing bacterial vaginosis. These risk factors for BV include:

However, the role of sexual activity in the development of the condition is not fully understood, and although most experts believe that bacterial vaginosis does not occur in women who have not had sexual intercourse, others feel that the condition can still develop in women who have not had sexual intercourse.

Can you get bacterial vaginosis (BV) from a sexual partner?

The term "vaginosis" refers to a vaginal abnormality; therefore a male cannot "get" bacterial vaginosis. However, female sex partners of women with bacterial vaginosis may want to consider being evaluated because it can spread to female partners.

Is bacterial vaginosis contagious (BV)?

Although bacterial vaginosis is not considered to be a contagious condition, the role of transmissibility of bacteria among individuals is not fully understood. Since having multiple or new sexual partners increases a woman's risk of developing bacterial vaginosis, this suggests that the spread of bacteria among individuals may alter the balance of bacteria in the vagina and potentially predispose to the development of bacterial vaginosis. However, since bacterial vaginosis also occurs in celibate women, other causative factors must also play a role in its development.

It is not possible to contract bacterial vaginosis from toilet seats, swimming pools, hot tubs, or from touching contaminated objects.

Is there a test to diagnose bacterial vaginosis (BV)? What is the "whiff test?"

When a woman notices an unusual vaginal discharge and reports this to her doctor, he or she will ask her a series of routine questions to help distinguish mild from more serious conditions. Additional issues that might indicate the presence of a more serious condition include:

  • fever,
  • pelvic pain,
  • new or multiple sexual partners (especially with unprotected intercourse), and
  • a history of sexually-transmitted infections (STDs).

In addition to these questions, the doctor will perform a pelvic exam. During the exam, the doctor notes the appearance of the vaginal lining and cervix. The doctor will also perform a manual exam of the ovaries and uterus. The cervix is examined for tenderness, which might indicate a more serious infection. The doctor may collect samples to check for Chlamydia or gonorrhea infection.

Examining the vaginal discharge under the microscope can help distinguish bacterial vaginosis from infections such as yeast vaginitis (vaginal yeast infection, Candidiasis) and trichomoniasis. A sign of bacterial vaginosis under the microscope is a vaginal cell called a clue cell. Clue cells are vaginal cells covered with bacteria and are believed to be the most reliable diagnostic sign of bacterial vaginosis. In addition to clue cells, women with bacterial vaginosis have fewer of the normal vaginal bacteria, called lactobacilli. A vaginal pH greater than 4.5 is also suggestive of bacterial vaginosis. Cultures of bacteria are generally not useful in establishing the diagnosis of bacterial vaginosis since it is caused by bacteria that are normally present in the vagina.

During the diagnosis of bacterial vaginosis, the doctor may perform a "whiff test" with potassium hydroxide (KOH) liquid. When a drop of KOH testing liquid used in the "whiff test" contacts a drop of the discharge from a woman with bacterial vaginosis, a certain fishy odor can result.

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What is the treatment for bacterial vaginosis (BV)?

What medicine treats bacterial vaginosis and recurrent BV? Can antibiotics cure it?

Bacterial vaginosis can be cured with antibiotics. Even after a woman has been cured, however, BV often recurs. The second course of antibiotics is necessary if a woman experiences recurrent bacterial vaginosis that produces symptoms.

Antibiotics are the recommended treatment for bacterial vaginosis. A few antibiotic remedies are routinely used and include:

  • metronidazole taken by either oral (pill) form or vaginal metronidazole gel. Oral metronidazole can cause some minor but unpleasant side effects but is believed to be the most effective treatment. The gels do not typically cause side effects, although yeast vaginitis can occur as a side effect of the medication.
  • vaginal clindamycin cream
  • tinidazole is an antibiotic that appears to be effective in treating bacterial vaginosis and may have fewer side effects than metronidazole.

Recurrence of bacterial vaginosis is possible even after successful treatment. More than half of those treated experience recurrent symptoms within 12 months. It is unclear why so many recurrent infections develop. With recurrent symptoms, a second course of antibiotics is generally prescribed.

Treatment of bacterial vaginosis in pregnant women is recommended to decrease the risk of pregnancy-associated complications related to infection. Treatment before Cesarean delivery, total abdominal hysterectomy, and insertion of an IUD is also recommended by most experts.

Can bacterial vaginosis (BV) be treated and cured with home remedies?

There are no home remedies or natural remedies for bacterial vaginosis. Antibiotics are the only treatment. It is important to note that douching (rinsing the interior of the vagina) will not help with BV, and there is no proven medical benefit of douching. Douching may flush bacteria farther up the genital tract into the uterus or Fallopian tubes, potentially worsening the condition.

Studies of yogurt/lactobacilli probiotic preparations (either taken orally or applied to the vagina), which are designed to help reestablish the lactobacilli population in the vagina, have not shown consistent results in treating bacterial vaginosis.

What is the treatment for recurrent BV? How is it treated during pregnancy?

While up to 1/3 of cases of bacterial vaginosis may resolve on their own, it is recommended that medical treatment be given if symptoms are present or during pregnancy to avoid the development of complications.

What about recurrent bacterial vaginosis?

Bacterial vaginosis may recur even after successful treatment. More than half of those treated experience recurrent symptoms within 12 months. It is unclear why so many recurrences develop. With recurrent symptoms, a second course of antibiotics is generally prescribed. Recurrent bacterial vaginosis may develop in the same woman after she has been treated so it is important to see a doctor if symptoms persist or recur. Up to 50% of women who are treated will develop a recurrence of symptoms in the year following treatment.

How is bacterial vaginosis treated during pregnancy?

Treatment of bacterial vaginosis in pregnant women is recommended to decrease the risk of pregnancy-associated complications related to infection. Treatment before Cesarean delivery, total abdominal hysterectomy, and insertion of an IUD is also recommended by most experts.

A return visit to your doctor is recommended if your symptoms do not resolve after treatment with antibiotics or if symptoms return.

What are the complications of bacterial vaginosis (BV)?

Bacterial vaginosis can resolve completely without complications after treatment. No special follow-up is necessary if the symptoms disappear.

Women with bacterial vaginosis are at increased risk for contracting HIV infection as well as other STDs including genital herpes, gonorrhea, and Chlamydia.

In pregnancy, bacterial vaginosis has been linked to premature labor, but the exact relationship is still not clear. BV has also been linked to miscarriages and other problems, so treatment during pregnancy is advised.

Can bacterial vaginosis (BV) be prevented?

Because the cause and development of bacterial vaginosis are poorly understood, it can be difficult to take measures to prevent it from occurring. Reducing certain risk factors, such as limiting the number of sex partners, avoiding the use of vaginal douches, and taking all medications as directed when being treated for bacterial vaginosis, can help reduce a woman's risk of developing bacterial vaginosis, and help reduce a woman's risk of developing bacterial vaginosis.

Medically Reviewed on 7/11/2023

Centers for Disease Control and Prevention. "Bacterial Vaginosis."

Gired, P. H., MD. "Bacterial Vaginosis." Medscape. Updated: Oct 25, 2018.

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Gired, P.H., MD. "Bacterial vaginosis." Medscape. Updated: Sep 25, 2017.
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