What is bacterial vaginosis?

Bacterial vaginosis is vaginal condition that can produce vaginal discharge and results from an overgrowth of normal 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 there are a number of species of bacteria that naturally live in the vaginal area and may grow to excess. The Gardnerella organism is not the sole culprit causing the symptoms. When these multiple species of bacteria become imbalanced, a woman can have a vaginal discharge with a foul odor.

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.

What are the symptoms of bacterial vaginosis?

The symptoms of bacterial vaginosis are vaginal discharge and odor. Usually, there are no other symptoms. 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.

Many women with bacterial vaginosis actually have no symptoms at all. Others experience an unpleasant fishy odor with vaginal discharge. The discharge is usually thin and grayish white. The discharge is often more noticeable after sexual intercourse.

What causes bacterial vaginosis?

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 the problem 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 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 infection is unknown.

Certain factors have been identified that increase the chances of developing bacterial vaginosis. These include multiple or new sexual partners, vaginal douching, and cigarette smoking. However, the role of sexual activity in the development of the condition is not fully understood, and bacterial vaginosis can still develop in women who have not had sexual intercourse.

How is bacterial vaginosis diagnosed?

When a woman reports an unusual vaginal discharge, the doctor 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.

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 yeast vaginitis (candidiasis) and trichomonas (a type of sexually transmitted infection). A sign of bacterial vaginosis under the microscope is an unusual vaginal cell called a clue cell. Clue cells 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.

Finally, 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.

What is the treatment for bacterial vaginosis?

Treatment for bacterial vaginosis consists of antibiotics. A few antibiotics are routinely used. Metronidazole (Flagyl) taken by either oral (pill) form or by vaginal metronidazole gel (Metrogel) is an effective treatment. Also available is the vaginal clindamycin cream (Cleocin). The 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.

Tinidazole is an antibiotic that appears to have fewer side effects than metronidazole and is also effective in treating bacterial vaginosis.

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.

What are complications of bacterial vaginosis?

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

In pregnancy, bacterial vaginosis can cause premature labor, premature birth, infection of the amniotic fluid, and infection of the uterus after delivery. However, treatment of asymptomatic (not producing symptoms) bacterial vaginosis in pregnancy has not been shown to decrease the incidence of premature births in most studies. For these reasons, screening and treatment for bacterial vaginosis during pregnancy is controversial, and research is still being conducted to determine its utility and value. Currently the routine screening of all pregnant women is not recommended. However, screening and treatment of bacterial vaginosis is sometimes recommended for women with a history of a preterm birth.

Bacterial Vaginosis At A Glance

• Bacterial vaginosis is an abnormal vaginal condition that is characterized by vaginal discharge and results from an overgrowth of normal bacteria in the vagina.
  
  
• Bacterial vaginosis is not dangerous, but it can cause disturbing symptoms.
  
  
• Symptoms of bacterial vaginosis are vaginal discharge and odor, although 50% to 75% of women with the condition experience no symptoms.
  
  
• In diagnosing bacterial vaginosis, it is important to exclude other serious infections, such as gonorrhea and chlamydia.
  
  
• Treatment options for bacterial vaginosis include oral antibiotics and vaginal gels.
  
  
• Serious complications of bacterial vaginosis can occur during pregnancy, and recurrence is possible even after successful treatment.

Previous contributing author: Carolyn Janet Crandall, M.D.