What is bacterial vaginosis?

bacterial vaginosis (BV) is a common but frustrating condition where the bacterial balance in the vagina is out of sync. Normally, the body is able to maintain an ideal balance. But if the balance is disrupted, certain types of bacteria can overgrow and cause symptoms.

BV is easy to treat and usually does not cause any other health problems. That being said, it can increase the risk of sexually transmitted diseases (STDs) or cause birth complications in pregnant women.

This article looks at the symptoms, causes, and risk factors for bacterial vaginosis. It also explains how to diagnose, treat, and prevent BV.

bacterial vaginosis symptoms

Of the 21 million women in the United States who are thought to have bacterial vaginosis each year, only about 3 million actually have symptoms.

When they do, symptoms of BV tend to be mild but persistent and may include:

  • gray or yellow vaginal discharge
  • ‘fishy smell’ that gets worse after sex
  • burning sensation when urinating
  • vaginal itching, redness, and swelling
  • vaginal bleeding after sex

Although BV symptoms are rarely serious, they can weaken vaginal tissue and increase the risk of gonorrhea, chlamydia, Trichomoniasisand HIV.

If infection occurs during pregnancy, it increases the risk of preterm birth (premature birth), low birth weight, and, in rare cases, miscarriage.


Symptoms of bacterial vaginosis include a fishy-smelling vaginal discharge. Itching, redness, swelling, burning with urination, and bleeding during intercourse are also common.

Signs and symptoms of bacterial vaginosis


Bacterial vaginosis occurs when the levels of “good” bacteria in the vagina suddenly drop. This allows “bad” bacteria to overgrow.The main “good” bacteria, called Lactobacilluswhich makes the vagina slightly acidic so that “bad” bacteria cannot overgrow.

Sex can trigger BV by introducing new or excess bacteria into the vagina.

Some of the more common causes of BV include:

  • bareback sex
  • multiple sexual partners
  • new sex partner
  • shared sex toys
  • rinse
  • bubble bath
  • vaginal deodorant
  • smokes
  • Intrauterine Device (IUD)

Genetics is also thought to play a role, either by promoting inflammation or by causing a deficiency in the production of lactobacilli.


Sex can lead to bacterial vaginosis by introducing new bacteria into the vagina, especially if you don’t use condoms or have multiple sexual partners. Smoking, douching, and IUDs also increase risk.

Causes and Risk Factors of Bacterial Vaginosis


Because bacterial vaginosis is not caused by a single factor, diagnosis is largely based on a review of your medical history and symptoms, as well as various laboratory tests and procedures.

These include:

  • pelvic exam
  • pH test to check vaginal acidity
  • Microscopic evaluation of vaginal fluid

Microscopy looks for “clue cells” (bacteria-laden vaginal cells). Agram stains can also be used to distinguish “good” bacteria from “bad” bacteria, allowing laboratories to check for imbalances in the vaginal flora.

Additional tests may be done to rule out other possible causes, such as a yeast infection or genital herpes.


The diagnosis of bacterial vaginosis usually includes a review of symptoms and medical history, a pelvic examination, vaginal pH testing, and microscopic evaluation of vaginal fluids.

How to Diagnose Bacterial Vaginosis


The standard treatment for bacterial vaginosis is a short course of antibiotic medication. Antibiotics are a class of medicines designed to treat bacterial infections.

The first line of options is Flagyl (Metronidazole) and Clindamycin. Both are very effective in treating BV with relatively few side effects.

Preferred first-line options include:

  • Metronidazole 500 milligrams (mg) orally twice daily for 7 days
  • Metronidazole 0.75% vaginal gel once daily for five days
  • Use clindamycin 2.0% vaginal ointment for 7 days at bedtime

Alternative treatments include clindamycin vaginal suppositories or Tindamax (Tinidazole) tablets. Although these drugs are effective, relapses are common and multiple treatments may be required to completely clear the infection.

Side effects include nausea, stomach pain, cough, sore throat, runny nose and a metallic taste in the mouth.

In addition to antibiotics, some supportive treatments may help. These include probiotics (good live bacteria found in yogurt and probiotic supplements) that may help prevent relapse. Boric acid (available in capsules and vaginal suppositories) is an ancient drug attracting new medical interest.

During treatment, wear loose-fitting pants or skirts to reduce vaginal moisture and heat that can promote bacterial growth. You can also reduce itching and swelling by applying a cool cloth to your vagina or splashing it with cold water.


First-line antibiotics used to treat bacterial vaginosis include oral metronidazole (aka Flagyl), topical metronidazole, and topical clindamycin.

Treatment options for bacterial vaginosis


As common as bacterial vaginosis is, there are things you can do to reduce your risk. These include safer sex and maintaining good vaginal hygiene.

Prevent bacterial vaginosis:

  • Limit the number of sexual partners.
  • Use condoms correctly and consistently.
  • Do not rinse.
  • Avoid bubble baths and vaginal deodorants.
  • Wipe from front to back after urinating.
  • Avoid IUDs if you have recurrent BV or have had severe BV in the past.


You can reduce your risk of BV by practicing safer sex, avoiding douching, and wiping from front to back after urinating. If you have recurrent BV, you may be advised to avoid IUDs.


Bacterial vaginosis (BV) is a common infection caused by an imbalance in the vaginal flora. When “good” bacteria such as lactobacilli are abnormally low, “bad” bacteria can overgrow, causing vaginal redness, itching, swelling, and a fishy-smelling discharge.

Sexual activity can cause BV by introducing new bacteria into the body. Risk factors include condomless sex, multiple sexual partners, smoking, douching, and IUDs.

Diagnosis of BV usually includes a pelvic examination, vaginal pH testing, and microscopic evaluation of vaginal fluid. BV is treated with oral or topical antibiotics, most commonly metronidazole and clindamycin.

The risk of BV can be reduced by practicing safe sex, avoiding douching, and wiping from front to back after urinating. People with recurrent or severe BV may be advised to avoid IUDs.

VigorTip words

Bacterial vaginosis can occur even with the best precautions. Try not to stress that it does. Instead, seek treatment and do everything you can to keep the condition from getting worse.

If antibiotics are prescribed, do not stop them early, even if symptoms go away. If you do this, antibiotic resistance can develop, making it harder to treat if the infection recurs.

Facts Every Woman Should Know About Bacterial Vaginosis