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Bacterial vaginosis (BV)

Bacterial vaginosis (BV) is the most common cause of vaginal discharge. It is not an STI but it is more common in women who are sexually active.

Here are some key facts:

  • 50% of women don’t experience symptoms but those that do develop a fishy vaginal discharge that may be white, grey and/or watery 
  • BV can occur in women who are not sexually active but is more common in those that are
  • Tests for BV involve taking a swab of cells from the vagina
  • It can be passed between female partners but not to men 
  • There is no equivalent in men
  • BV is easily treated with antibiotics but can keep coming back
  • It is not serious but can be during pregnancy as it may increase the risk of complications such as premature birth and miscarriage

You can read about bacterial vaginosis in more detail below.

Signs and symptoms of bacterial vaginosis

Half of women with BV will not experience any symptoms but those that do tend to experience unusual vaginal discharge. This discharge can have a strong fishy smell (particularly after sex) and can be white or grey and watery.

BV does not cause itchiness or soreness and if those symptoms develop, there may be another condition affecting the vagina.

The causes and how it's passed on

BV is known to upset the natural balance of bacteria in the vagina but what causes BV is a bit of a mystery. It is also not understood why BV can be passed between female sexual partners but cannot be passed from female to male sexual partners.

You are more likely to develop BV if you:

  • Use scented soaps or bubble baths
  • Have an IUD fitted
  • Use vaginal deodorant
  • Douche (clean out the vagina)
  • Use strong detergents to wash your underwear
  • Are a smoker

Other factors that may play a role are hormonal changes, semen in the vagina and contraceptive devices that are fitted in the uterus (IUS or IUDs).

You cannot get BV from hugging, sharing baths or towels, swimming pools, toilet seats or from sharing cups, plates or cutlery.

Testing for bacterial vaginosis

A doctor or nurse may be able to diagnose BV by a description of your symptoms and by examining your vagina.

They may also take a sample of cells from your vagina, by brushing a sort of cotton bud or a small plastic loop over the inside of the vagina. It may be a little uncomfortable but shouldn’t be painful.

The sample will usually be sent to a lab for testing to look for signs of BV and you will normally get your result within a week.

They may also test the acidity (pH level) of your vagina. This is a good way to test for BV because BV causes the acidity of your vagina to change.

If you have no symptoms, there is no routine test for BV and cervical smear tests and routine blood tests will not detect BV.

You can be tested and receive treatment for BV at some Brook services, your GP surgery or at GUM or sexual health clinics

Treatment of bacterial vaginosis

BV can go away by itself but is easily treated with antibiotics. There are a number of antibiotics that can be used and may be prescribed as a single dose or as a longer course.

You may be given a cream or gel instead that you use in the vagina for around a week. Be aware that some of these creams can weaken the latex in condoms, diaphragms and caps but ask the doctor or nurse who gives you the cream for more advice.

Some types of antibiotics can’t be mixed with alcohol but the doctor or nurse who prescribes your treatment will advise you further.

BV is not serious unless you are pregnant when it can cause complications. But don’t worry, it can still be safely treated. Make sure you inform the doctor or nurse if you are (or think you are) pregnant so that they can take this into consideration.

It is not uncommon for women to experience repeated episodes of BV. Treatment for this can vary. If you use an IUD or IUS (both contraceptive methods that sit in the vagina) then your doctor or nurse may recommend you try a different method.

Page last reviewed: September 2015
Next review due: September 2017