Bacterial Vaginosis

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This photomicrograph of a vaginal smear specimen depicts two epithelial cells, a normal cell, and an epithelial cell with its exterior covered by bacteria giving the cell a roughened, stippled appearance known as a “clue cell”. –

Bacterial vaginosis or “BV” is a type of vaginal infection that is poorly understood. Women at any age can have it – even teens and women who have never been sexually active. It tends to be more common among girls and women who have had sex with one or more partners.

What causes bacterial vaginosis?

Bacterial vaginosis is a vaginal infection caused by an overgrowth of anaerobic bacteria and an organism called Gardnerella vaginalis. “Anaerobic” means the bacteria doesn’t need any oxygen to survive or grow. Small amounts of these anaerobic bacteria and Gardnerella can normally be found in your vagina. Bacterial vaginosis occurs when the balance of organisms in your vagina is upset and the anaerobic bacteria overgrow. The good, protective bacteria Lactobacilli are then outnumbered and not able to do their normal job, which is to make a natural disinfectant which helps keep organisms at the normal, healthy balance in your vagina. When this happens, an infection occurs.


The exact reasons that bacteria overgrow are not known. Bacterial vaginosis (often called BV) is not considered a sexually transmitted infection but it is more common in women with multiple sexual partners. BV may also occur after sexual intercourse with a new partner and after douching. Lesbian women also get bacterial vaginosis, and even women who have never been sexually active can have BV.

clue cells vs. normal vaginal cells

Clue cells vs. normal vaginal cells

What are the signs/symptoms of bacterial vaginosis (BV)?

It’s a fact that 50-75% of women who have BV don’t have any symptoms but those who do often complain of a fishy smelling vaginal odor and a milky-white, or gray vaginal discharge. The discharge may be light or heavy. The odor may get worse around the time of menstruation or after unprotected sexual intercourse. When semen (male sperm) mixes with vaginal secretions, the odor becomes stronger. Less common symptoms include: vaginal itchiness, redness, and pain with intercourse.

Your health care provider may notice vaginal discharge or odor during your routine pelvic exam and do a test of the vaginal fluid to see if you have BV or any other vaginal infections. If you do have BV, your health care provider will give you a prescription to treat it.

How is bacterial vaginosis (BV) diagnosed?

The only way to diagnose BV is by an exam by your health care provider (HCP) and testing the vaginal discharge. Your HCP will use a cotton swab to take a sample of your vaginal discharge. He/she can then measure the acidity of the discharge with pH paper. If your vagina is less acidic than it should be (pH of more than 4.5), this may be a sign that you may have bacterial vaginosis. Your HCP can look at the sample under a microscope. If the normal bacteria (lactobacilli) are not there but many “clue” cells (cells from the vaginal lining that are coated with bacteria) are present, you have bacterial vaginosis.

How is bacterial vaginosis (BV) treated?

If you have bacterial vaginosis, your health care provider will likely either give you a prescription for a cream or gel that you put into your vagina with an applicator or a prescription for pills that you take by mouth. You should let your HCP know about any other medications that you are taking. If you use a vaginal cream or gel, you should NOT use tampons during the treatment because it will absorb the medication and make it less effective. Metronidazole or clindamycin are two antibiotics used to treat bacterial vaginosis. The medication works pretty quickly to cure BV, but you need to make sure that you take ALL of the medication for it to work. Many women choose the vaginal gel because the pills can cause nausea and a metal taste in your mouth. Others prefer the oral medication because they don’t want to insert a cream in the vagina. Both are effective.

  • You should not use douches or vaginal deodorant sprays. Although they may help cover up the odor, they will not cure the infection, and they might make your infection worse.
  • Condoms may help to lessen the chance of getting BV if you are sexually active because the semen doesn’t change the bacteria in the vagina. Even though BV is more common in young women who have sexual intercourse with many partners, treatment of a male partner does not prevent future BV infections.

Can I get bacterial vaginosis again?

Unfortunately, bacterial vaginosis often comes back, even if you take all of your medication and follow the advice from your health care provider (HCP). If your symptoms come back, see your HCP. You may need to be treated twice a week for a longer time.

Can bacterial vaginosis cause any other problems?

Bacterial vaginosis can increase your chance of getting a serious pelvic infection called pelvic inflammatory disease (PID), or an infection after a vaginal or uterus operation. It can also increase your chance of having problems with pregnancy such as low-birth weight babies or premature delivery (delivery before the normal 9 months). Treatment is important in pregnant women who have had premature babies in the past. If bacterial vaginosis is treated early, the risks of getting any of these problems are low.

Are there any complications from bacterial vaginosis if it’s not treated?

Most of the time BV is treated and doesn’t cause any problems. However, there are some serious risks you should know about. Having BV can put you at risk for other sexually transmitted infections.

If left untreated, BV can cause pelvic inflammatory disease, which can damage your reproductive organs and cause fertility problems later. Pregnant women who have BV are more likely to have premature babies or babies that have a low birth weight (<5.5 pounds).

Health care providers and scientists don’t completely understand BV, but they do know that there are some basic ways to lower the chance of getting it, which includes: abstinence, using condoms, and avoiding douching. If you do get BV, be sure to take ALL of the medicine your HCP prescribes even if your symptoms go away.