Women’s Health

Bacterial Vaginosis

Bacterial vaginosis, or BV, is not necessarily a sexually transmitted disease, though sexual activity clearly plays a role for many women. Bacterial vaginosis is the name of a condition in women characterized by a disruption in the balance of bacteria normally found in the vagina. It is present in almost 30% of women in this country ages 14-49 making it the most common cause of vaginal discharge in women of childbearing age. About 50-75% of women with BV don’t have any symptoms. Those with symptoms often complain of an unpleasant “fishy smelling” discharge that is more noticeable after intercourse. The discharge, when present is off-white, grey and thin. Rarely, women may complain of burning during urination or itching around the outside of the vagina.

What is BV?

The vaginal flora (microbiologic environment) is made up of many microscopic organisms including various bacteria and yeast. There is a “balance” of organisms with a “normal” percentage of E. Coli, lactobacilli, klebsiella and a host of other microbes that make up the vagina. This balance can be shifted by changing pH (acidity) of the vagina. With bacterial vaginosis there is a shift away from these microorganisms, and in particular, lactobacilli to other organisms such as Mycoplasma hominis, Prevotella species, Bacteroides species, Peptostreptococcus species as well as others. The exact mechanism by which the floral balance changes is uncertain and the role of sexual activity is also unknown.

Who is at risk for getting BV?

The risk factors include new sexual partners, multiple partners, douching and cigarette smoking. It’s important to note that BV can happen in women who’ve never had intercourse. Women can also transmit BV to other women suggesting that oral-genital sex may be an important risk factor.

How is the diagnosis of BV made?

The most common way to diagnose BV is simply to observe a thin, grayish-white discharge that smoothly coats the vaginal walls. The vaginal pH is generally over 4.5 suggesting that the balance of lactobacilli is diminished—as this makes the vagina ‘more acidic’ thereby lowering its pH. A microscopic analysis also reveals “clue cells” that are present. Cultures taken from the vagina are frequently positive for Gardenerella vaginalis an organism frequently found in women with BV. That said, Gardenerella vaginalism is found in almost half of all women without symptoms of BV.

Implications of BV

It is believed that women with BV have a greater incidence of pre-term delivery with pregnancy. The major implication for women, however, is the presence of a discharge or a “fishy” odor.

BV may be a risk factor for infection with genital herpes, gonorrhea and chlamydia though the exact mechanism of this is unknown.


These infections generally respond well to treatment with either metronidazole (taken as a tablet or vaginal gel) or clindamycin. Whether or not your partner will need to be treated is a subject you should discuss with your health care provider.


In summary, bacterial vaginosis (BV) is not an infection–it is a change in the colonization or flora of the vagina. This change may lead to a foul odor, a discharge or vaginal irritation. It may be sexually acquired, hence its listing in this webpage, but not necessarily. It is associated with multiple sex partners but does not require penile intercourse and has been associated with oral-genital sex. It’s implications for your overall health is debated though it clearly plays a role in pregnancy and may play a role in increasing the likelihood of postoperative infections following hysterectomy and even abortions. It is not clear that your partner should be treated if you have BV, though this may be tried if you have recurrences. BV is commonly found in women though often in an asymptomatic form. If you have been diagnosed with BV do not—I repeat do not—go home and confront your sexual partner of infidelity! Ask your health care provider and consult some of these websites for further information.