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Bacterial vaginosis

Bacterial vaginosis (BV) is a common infection of the vagina.

It can cause a change in how your vaginal discharge looks. It can also cause your discharge to have an unusual smell.

It is easy to treat.

Non-urgent advice: Contact your GP, midwife or obstetrician if:

  • you think you have bacterial vaginosis

It's important to get treatment if you're pregnant. There's a small chance it can cause complications with pregnancy.

Symptoms of bacterial vaginosis

The symptoms of bacterial vaginosis are usually:

  • a change in the colour or texture of your normal vaginal discharge
  • an unusual smell coming from your vagina or discharge

Your discharge may become more watery. It might also look grey.

The unusual smell is sometimes compared to the smell of raw fish.

Causes of bacterial vaginosis

The cause of bacterial vaginosis is not fully understood. But it happens when the type of bacteria in your vagina changes.

In your vagina you have a mixture of bacteria. This includes 'good' bacteria called lactobacilli.

If the good bacteria die off, other types of bacteria begin to grow. These are called anaerobic bacteria.

This change in bacteria upsets the acid balance (PH balance) of your vagina. This can cause 'bad' anaerobic bacteria to grow and cause BV.

Diagnosing bacterial vaginosis

Non-urgent advice: Contact your GP, obstetrician or midwife if:

  • you notice a change in the colour or smell of your vaginal discharge

Your GP, obstetrician or midwife may ask you some questions about the discharge. They may also examine you by looking at your vagina.

They may ask you if they can take a vaginal swab. This is often the best way to confirm if you have bacterial vaginosis.

Your GP, nurse or midwife will use a speculum to take the swab. This is a small plastic device that is inserted into your vagina and opened gently.

The swab will be sent to a lab for analysis.

Vaginal swabs do not usually hurt, but they may be a little uncomfortable. They do not harm your baby.

Treatment of bacterial vaginosis

Your GP or obstetrician can prescribe an antibiotic to treat BV. It may come as tablets, a cream or a gel.

Always follow the instructions given to you by your GP, obstetrician or pharmacist.

Self-management of bacterial vaginosis

There are things you can do to self-manage BV, along with antibiotics.


Use plain water when you are washing your genitals.

If you would like to use something else to wash your genitals, don't use soap or shower gel.

Soap can irritate the skin and alter the pH balance in the vagina. It is never recommended for washing your genitals.

Instead, use an emollient like aqueous cream. Emollients can make your bath or shower very slippery.

It is better to take showers rather than baths if you have bacterial vaginosis. Bathing is more likely to alter the pH balance in your vagina because you are sitting in the water.

You do not need to clean your vagina more than once per day.

PH balance in your vagina - what it means

Your vaginal pH helps to tell your overall vaginal health. A normal pH is usually less than 4.5, but it can vary with age and where you are in your period cycle.


  • do not douche your vagina (a douche is flushing, squirting or spraying water or other cleaning products into your vagina)

  • do not use tampons when you are pregnant - these can introduce bad bacteria

  • do not use shower gels, shampoo or antiseptics to wash your genitals

  • do not use deodorants on your vagina or vaginal washes


Smoking can affect your immune system. This can make you more prone to getting bacterial vaginosis.

Quitting smoking can reduce your chances of getting bacterial vaginosis.

Get help to quit smoking

Smoking during pregnancy

Bacterial vaginosis in pregnancy

For most pregnancies, bacterial vaginosis does not cause any problems.

But in some cases, there’s a risk of complications, such as premature birth or miscarriage.

Get treatment for bacterial vaginosis if you have it and are at risk of premature birth.

Antenatal perineal massage

Do not do perineal massage when you have bacterial vaginosis. It is not recommended.

Page last reviewed: 19 November 2023
Next review due: 19 November 2026