Bacterial vaginosis (BV) is a common infection that happens from a change in the normal balance of vaginal bacteria. When more harmful bacteria grow than good bacteria, a BV infection can occur.
BV doesn’t always cause symptoms. But when it does, you might have pain or discomfort when you pee or have sex and a fishy-smelling vaginal discharge.
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Doctors define bacterial vaginosis (BV) as a bacterial infection in the vagina.
A healthy vagina has a balance of good bacteria and harmful bacteria. Usually, good bacteria keep harmful bacteria in check. But when the normal balance is upset, and the harmful bacteria grow to outnumber the good bacteria, bacterial vaginosis is the result.
Bacterial vaginosis isn't a sexually transmitted infection (STI). But sexually active people — particularly those with more than one sex partner — are more at risk of getting BV.
People who don't have vaginas and those who don't have sex rarely get BV. Sometimes, a BV infection doesn't cause symptoms and may clear up on its own.
BV is the most common vaginal condition among people ages 15 to 44 who have vaginas. Between 29% to 35% of people with vaginas will get bacterial vaginosis at some point in their lives. Rates are even higher among Black people with a vagina, with close to 50% getting BV.
Women who have not had anal, oral, or vaginal sex can still be affected, and 19% of those with BV are in that category. Pregnant people make up 25% of those who get BV.
Researchers and scientists don't completely understand how BV spreads or know how best to prevent it. What they do know is that lactobacillus — a type of healthy bacteria — keeps the vagina slightly acidic, which prevents bad bacteria growth. BV happens when lactobacillus levels drop and more bad bacteria move in.
You can't get a bacterial vaginosis infection from a public toilet seat or swimming pool.
Although they have some similarities, bacterial vaginosis and a vaginal yeast infection aren't the same thing.
Bacterial vaginosis is caused by bacteria, whereas a yeast infection is caused by an overgrowth of a fungus called candida.
However, the two infections are alike in that both:
Sometimes, you can tell the infections apart due to your symptoms, but not always. Yeast infections usually have no odor and involve a thick, white discharge that resembles cottage cheese.
When you have BV, your discharge will typically be thin and watery and white, gray, or greenish in color. It likely will have a fishy smell that gets stronger after sex. But not everyone with BV has vaginal discharge.
BV is not contagious to a male partner but may be spread during sex if both partners have vaginas. It’s not known exactly why or how sex increases the risk of BV, but people who are sexually active are more likely to get BV.
You can't catch BV from sharing bedding, clothing, towels, or other items with someone who has BV.
Yes, BV sometimes can go away without treatment, but more often, the infection will continue or get worse. BV also may come back if it isn’t fully treated.
What are bacterial vaginosis risk factors and complications?
Anyone with a vagina can get BV, but Black women are at the highest risk of BV at 51%. They're followed by Hispanic women at 32% and White women at 23%.
Your risk of BV is higher if you:
Left untreated, bacterial vaginosis has been tied to a higher risk of other health problems.
These include:
While BV isn't particularly harmful most of the time, it's important to treat bacterial vaginosis promptly, especially if you're pregnant. Research shows that BV is linked to an increased risk of certain pregnancy-related complications.
These include:
Having bacterial vaginosis while pregnant can also put you at risk of chorioamnionitis, an inflammation of the membranes around the baby in the uterus. This condition can increase your chance of a preterm birth and puts the infant at higher-than-normal risk of cerebral palsy, a movement and balance disorder.
There are ways to lower your risk of getting BV:
You can also work to maintain a healthy pH in your vagina, so your lactobacillus levels stay high and bad bacteria can't take over.
To help maintain the delicate balance of organisms in your vagina:
Most people (84%) who have BV report no symptoms.
But symptoms of BV may include:
Because BV symptoms mimic symptoms of other vaginal infections, it’s important to get a proper diagnosis and treatment plan.
Call your doctor if you:
To confirm a BV diagnosis, your doctor will:
There are many BV home test kits on the market, but they're not always accurate — some boast of being 90% reliable. To ensure your diagnosis, visit your health care provider.
Although BV can go away on its own, you may need treatment — usually a five- to seven-day course of an antibiotic.
Keep in mind that BV symptoms can worsen after having sex. Plan to avoid sexual contact until you're done taking your medicine and your symptoms are gone.
Sex partners with a penis don't need to be treated. However, BV can spread between female sex partners. If your sex partner also has a vagina, they may want to see their provider to find out if they need treatment.
To treat BV, your provider can prescribe a form of antibiotics.
These medications include:
Metronidazole, secnidazole, and tinidazole can cause nausea or stomach pain, especially if you drink alcohol during or after treatment. Avoid alcohol while on these medications.
Make sure to finish your entire course of medication — even if your symptoms go away or the medication seems to be taking a long time to work — to prevent a BV recurrence.
Researchers aren’t sure why, but recurrent BV is very common. Half of all people with BV will get it again within one year, even if the original infection clears up. Sometimes, BV can even become chronic.
If BV recurs, your provider may need to put you on a long-term course of antibiotics.
Recurrence is more likely if:
If you use an IUD and have recurrent BV, ask your provider about using a different kind of birth control.
Last reviewed by a UPMC medical professional on 2024-09-05.
