What Causes Bacterial Vaginosis and How to Diagnose it?

Any women can get BV.Some women with BV don't know they have it because they have no symptoms.Women who have never had sexual intercourse may also be affected by BV, and it is common in pregnant women.Having BV can increase a woman's susceptibility to other STDs. Pregnant women may deliver premature or low birth-weight babies.In addition,many women don’t know what causes BV and how to diagnose BV.

What causes BV?

Although BV can be associated with sexual activity, there is no clear evidence of sexual transmission. It is possible for sexually inactive persons to get infected with bacterial vaginosis. Rather, BV is a disordering of the chemical and biological balance of the normal flora. Recent research is exploring the link between sexual partner treatment and eradication of recurrent cases of BV. Pregnant women and women with sexually transmitted infections are especially at risk for getting this infection. Bacterial vaginosis may sometimes affect women after menopause. A 2005 study by researchers at Ghent University in Belgium showed that subclinical iron deficiency (anemia) was a strong predictor of bacterial vaginosis in pregnant women.A longitudinal study published in February 2006 in the American Journal of Obstetrics and Gynecology showed a link between psychosocial stress and bacterial vaginosis independent of other risk factors.

How to diagnose BV?

To make a diagnosis of bacterial vaginosis, a swab from inside the vagina should be obtained. These swabs should be tested for:
- A characteristic "fishy" odor on wet mount. This test, called the whiff test, is performed by adding a small amount of potassium hydroxide to a microscopic slide containing the vaginal discharge. A characteristic fishy odor is considered a positive whiff test and is suggestive of bacterial vaginosis.
- Loss of acidity. To control bacterial growth, the vagina is normally slightly acidic with a pH of 3.8–4.2. A swab of the discharge is put onto litmus paper to check its acidity. A pH greater than 4.5 is considered alkaline and is suggestive of bacterial vaginosis.
- The presence of clue cells on wet mount. Similar to the whiff test, the test for clue cells is performed by placing a drop of sodium chloride solution on a slide containing vaginal discharge. If present, clue cells can be visualized under a microscope. They are so-named because they give a clue to the reason behind the discharge. These are epithelial cells that are coated with bacteria.
- Two positive results in addition to the discharge itself are enough to diagnose BV. If there is no discharge, then all three criteria are needed. Differential diagnosis for bacterial vaginosis includes the following:
- Normal discharge.
- Candidiasis(thrush, or a yeast infection).
- Trichomoniasis, an infection caused by Trichomonas vaginalis.