There is no clear explanation for what causes BV. Several studies have linked BV with vaginal douching, which can cause changes in the vagina. Although BV does not appear to be a sexually transmitted infection, it is almost always found in sexually active women. Most cases of bacterial vaginosis occur in sexually active women between the ages of 15 and 44, especially after contact with a new partner. Condoms may provide some protection. There is no evidence that spermicides increase BV risk. Pregnant women and women with sexually transmitted infections are especially at risk for getting this condition.

Many microorganisms are normally found in a healthy vagina. Lactobacillus, particularly the hydrogen peroxide-producing species, is a bacterium that appears to control the growth of other vaginal microorganisms by maintaining a normal acidity (pH) in the vagina. The microorganisms involved in BV are very diverse and include Gardnerella vaginalis, Mobiluncus species (spp.), Bacteroides spp. and Mycoplasma spp. If there is a loss of lactobacillus, which results in a change in the normal pH balance in the vagina, normal bacterial flora can multiply without limit, resulting in an overgrowth of bacteria that can produce toxins affecting the body's natural defenses and creating an environment in which healthy bacteria cannot grow.

Scientific studies suggest that BV is common in women of reproductive age. In the United States, as many as 16% of pregnant women have BV. This varies by race and ethnicity from 6% in Asians and 9% in whites to 16% in Hispanics and 23% in African Americans.

Women with BV often have an abnormal vaginal discharge with an unpleasant odor. Some women report a strong fish-like odor, especially after intercourse. The discharge is usually white or gray; it can be thin. Women with BV may also have burning during urination or itching around the outside of the vagina or both. Some women with BV report no signs or symptoms at all.

Bacterial vaginosis is not considered an infection. It is not known how long it takes for BV to develop, and studies are currently being done to understand the natural history of the condition. Women may have BV and have no symptoms. The overgrowth of bacteria probably takes days or weeks, depending on the cause of the change in vaginal flora.

What can happen if I get BV?

BV has been associated with:

• Pregnancy problems. BV has been associated with premature delivery and low birth weight babies (less than five pounds).
• PID. Pelvic inflammatory disease or PID can affect a woman's uterus, ovaries and fallopian tubes, which carry eggs from the ovaries to the uterus. Having BV increases the risk of getting PID after a surgical procedure, such as a hysterectomy or an abortion.
• Higher risk of getting other STDs. Having BV may increase the chances of getting STIs, such as chlamydia, gonorrhea and HIV. Women with HIV who get BV increase the chances of passing HIV to a sexual partner. It is uncertain whether having an STI can cause a vaginal imbalance.

In some cases, BV has been associated with premature delivery and babies born at low birth weight (less than five pounds). See your health care provider about treatment of BV during pregnancy.

Because there is evidence that BV is associated with douching and sexual activity, the following behaviors may help in preventing BV. Follow these guidelines:

• Don't douche. Douching removes some of the normal bacteria in the vagina that protects you from infection. This may increase your chances of getting BV. It may also increase the chances of BV coming back after treatment.
• Don't have sex. The best way to prevent any sexually related condition or STI is to practice abstinence, or not having vaginal, oral or anal sex.
• Be faithful. Having a sexual relationship with only one partner may reduce your chances of getting BV. Be faithful to each other; only have sex with each other and no one else.
• Use condoms. Protect yourself with a condom EVERY time you have vaginal, anal or oral sex. Condoms should be used for any type of sex with every partner. For vaginal sex, use a latex male condom or a female polyurethane condom. For anal sex, use a latex male condom. For oral sex, use a dental dam. A dental dam is used by dentists when doing dental work like filling a cavity. It is a square piece of rubbery material that stretches and can be placed over the anus or the vagina before sexual contact.
• Talk with your sex partner(s) about STIs and using condoms. It's up to you to make sure you are protected.
• Talk frankly with your doctor or nurse and your sex partner(s) about any STIs you or your partner has or had. Talk about any discharge in the genital area.
• Have regular pelvic exams. Talk with your doctor about how often you need them. Many tests for STIs and other related conditions can be done during an exam.
• If you are pregnant and have symptoms of BV or have a history of giving birth to a baby who was premature or was at low birth weight, get tested for BV. Get tested as soon as you think you may be pregnant.
• Finish your medicine. If you have BV, finish all the medicine that you are given to treat it. Even if the symptoms go away, you still need to finish all of the medicine.

No. You can get BV again.