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Bacterial Vaginosis

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Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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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. Symptoms may also mimic those found in yeast infections of the vagina and trichomoniasis (a sexually-transmitted infection), and these conditions must also be excluded in women with vaginal symptoms.

Bacterial vaginosis is a common condition, and studies have shown that approximately 29% of women in the US are affected. Bacterial vaginosis is found in about 16% of pregnant women and approximately 60% of women who have a sexually-transmitted disease (STD).

What are the symptoms of bacterial vaginosis?

Many women (about 85% of those affected) with bacterial vaginosis actually have no symptoms. When symptoms do occur, vaginal discharge and odor are the predominant symptoms. 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.

Some women may 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, intrauterine devices for contraception, recent antibiotic use, 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.