Bacterial vaginosis signs and symptoms may include:

• Thin, gray, white or green vaginal discharge
• Foul-smelling "fishy" vaginal odor
• Vaginal itching
• Burning during urination

Many women with bacterial vaginosis have no signs or symptoms.

Bacterial vaginosis results from overgrowth of one of several bacteria naturally found in your vagina. Usually, "good" bacteria (lactobacilli) outnumber "bad" bacteria (anaerobes). But if there are too many anaerobic bacteria, they upset the natural balance of microorganisms in your vagina and cause bacterial vaginosis.

Risk factors for bacterial vaginosis include:

• Having multiple sex partners or a new sex partner. Doctors don't fully understand the link between sexual activity and bacterial vaginosis, but the condition occurs more often in women who have multiple sex partners or a new sex partner. Bacterial vaginosis also occurs more frequently in women who have sex with women.
• Douching. The practice of rinsing out your vagina with water or a cleansing agent (douching) upsets the natural balance of your vagina. This can lead to an overgrowth of anaerobic bacteria, and cause bacterial vaginosis. Since the vagina is self-cleaning, douching isn't necessary.
• Natural lack of lactobacilli bacteria. If your natural vaginal environment doesn't produce enough of the good lactobacilli bacteria, you're more likely to develop bacterial vaginosis.

Bacterial vaginosis doesn't generally cause complications. Sometimes, having bacterial vaginosis may lead to:

• Preterm birth. In pregnant women, bacterial vaginosis is linked to premature deliveries and low birth weight babies.
• Sexually transmitted infections. Having bacterial vaginosis makes women more susceptible to sexually transmitted infections, such as HIV, herpes simplex virus, chlamydia or gonorrhea. If you have HIV, bacterial vaginosis increases the odds that you'll pass the virus on to your partner.
• Infection risk after gynecologic surgery. Having bacterial vaginosis may increase the risk of developing a post-surgical infection after procedures such as hysterectomy or dilation and curettage (D&C).
• Pelvic inflammatory disease (PID). Bacterial vaginosis can sometimes cause PID, an infection of the uterus and the fallopian tubes that can increase the risk of infertility.