BV happens when the usual balance of bacteria in the vagina changes. People with BV have:

• less of a type of bacteria called lactobacilli
• an overgrowth of other types of bacteria
• a change in pH (acid/alkaline balance) of the vagina with the vagina becoming more alkaline

It’s not yet clear why BV affects some people but not others, but it’s more common if you:

• smoke
• vaginally douche
• have had a recent change in sexual partner

Using products like antiseptics, bubble bath or shampoo in the bath, hormonal changes during the menstrual cycle, receiving oral sex, semen in the vagina after sex without a condom, using a copper IUD (copper coil) or hormonal IUD (hormonal coil) for contraception, and genetic factors may also play a part.

BV is not currently classed as a sexually transmitted infection, but people with a vagina who are sexually active and have had a change of partner, or have more than one partner, are more likely to have it.

BV is also found in people who have never had sex.

Around half of people with BV won’t have any signs and symptoms or may not notice them.

If you do get symptoms, you may notice a change in your usual vaginal secretions (discharge).

This may increase, become thin and watery, change to a white/grey colour and develop a strong, unpleasant fishy smell, especially after sex.

BV doesn’t usually cause soreness, itching or irritation.

If you think you may have BV, go to a GP surgery or sexual health clinic. They may recommend a test if you have signs and symptoms.

BV isn’t a sexually transmitted infection (STI) but go to a sexual health clinic or GP surgery if there’s a chance you may have an STI.

You may be offered a BV test during pregnancy if you have symptoms. You should be offered a test before some gynaecological procedures and before an abortion.

BV signs may be noticed during a cervical screening (smear) test or vaginal examination. You’ll only need treatment if the BV is bothering you. Routine blood tests don’t detect BV.

A test isn’t always needed. A doctor or nurse may:

• look at your vagina and any vaginal discharge
• use a swab to take a sample from the vagina, or you may be able to take your own swab.

A swab looks like a cotton bud but is smaller and rounded. It sometimes has a small plastic loop on the end rather than a cotton tip. It’s wiped over the parts of the body that could be affected. It only takes a few seconds and isn’t usually painful, though it may be uncomfortable for a moment.

Sometimes your test result will be available straight away, but it can take up to 2 weeks.

It’s possible to buy a BV test to do at home. The accuracy of these tests varies. If you buy a testing kit, get advice from a pharmacist or doctor.

• BV is usually treated with antibiotic tablets. Different antibiotics can be used. It may be a single dose or a longer course, up to 1 week
• You may be given cream, gel or tablets to use in the vagina instead, usually for 5 to 7 days
• If you’re given the antibiotic metronidazole, either as tablets or a vaginal gel, you’ll be advised not to drink alcohol during the treatment and for 48 hours afterwards
• Some creams can weaken latex condoms, diaphragms and caps. Polyurethane (soft plastic) types can be used instead. Ask the doctor, nurse or pharmacist for advice
• Tell the doctor, nurse or pharmacist if you’re pregnant, think you might be, or you’re breastfeeding.This can affect the type of treatment you’re given

• Treatment is effective at clearing BV within about 4 weeks, if used correctly
• It’s quite common for BV to return, and some people get it multiple times.

Only if signs and symptoms:

• don’t go away after about 4 weeks
• come back

For many people, BV goes away by itself.

Treatment is usually only needed if:

• the BV is bothering you
• you have BV symptoms when pregnant
• you’re having surgery that affects the cervix (entrance to the uterus)

It’s common for BV to come back. If it keeps coming back, it’s called recurrent BV.

There are different ways to treat recurrent BV. You may be given:

• a course of antibiotic gel to use over a few months
• antibiotic tablets to use at the start and end of your period

Some people may find it helpful to use a lactic acid gel (from a pharmacy). Ask your doctor, nurse or pharmacist for advice.

Using condoms during vaginal sex and stopping smoking may help lower the chance of developing BV.

For other ways to help keep your vagina and vulva healthy – also see below for What can I do to help keep my vagina healthy?

BV has been found in some people who have had a miscarriage, a premature (early) birth or a baby with a low birth weight.

If you have symptoms of BV during pregnancy, it’s important to go for a check-up so treatment can be given if needed.

BV can be treated safely when you’re pregnant or breastfeeding, but do tell the doctor or nurse as it may affect what treatment you’re offered.

There are some things you can do to help keep your vagina and vulva healthy. They may lower your chances of getting recurrent BV.

• Your vagina is self-cleaning. Avoid washing inside the vagina or douching because it can upset the natural balance of the vagina
• The vulva (the outside of the genitals which touches underwear) needs to be washed daily
• It’s advisable to avoid strongly perfumed soaps if you can. A mild soap and warm water is fine. If your skin is very sensitive, you may prefer a soap substitute or emollient
• There is never a need to use special vulva cleansing products or deodorants
• If you get recurrent BV, it may be advisable to shower rather than bath as this is less likely to wash away good bacteria from the vagina.
• Some bath products may cause skin sensitivities so avoid these if possible, and try to avoid putting disinfectant or antiseptic in the bath
• Avoid using scented period products and panty liners. Consider period pants or menstrual cups as a more skin- and eco-friendly option.Try not to wear panty liners every day
• Make sure your vagina is well lubricated before and during vaginal sex
• Try not to wear tight or synthetic clothes, like tights, nylon underwear, leggings, lycra shorts, and tight jeans or trousers every day
• Avoid using strong or scented laundry products for washing underwear

Online services cannot test for BV.

All check-ups, tests and treatment for STIs are free through NHS services.

Check-ups and tests for BV are free through NHS services. You may have to pay a prescription charge for BV treatment you get from a GP.

You’ll need to pay for any treatment that you get over the counter from a pharmacy.

A check-up or test can’t tell you how long you’ve had a particular infection.

There’s no need to tell a partner you have BV unless you want to.

Ask a doctor or nurse if BV treatment is advised for sexual partners with a vagina.

No. BV doesn’t cause cervical cancer.

No. BV will not affect your fertility or chance of getting pregnant.

The following will help protect you from getting and passing on most sexually transmitted infections (STIs).