Bacterial vaginosis (BV) is a fairly common condition that can cause unpleasant vaginal symptoms.

Women diagnosed with BV tend to have smaller numbers of lactobacilli, a bacteria found in the vagina responsible for creating a slightly acidic environment. When numbers of this bacteria are reduced, acidity levels are lowered, thus allowing for other unwelcome bacteria to grow.

On this page, you can find out:

What symptoms does BV cause?

Most women experience some form of vaginal discharge, and this is quite normal. But when the bacteria that cause BV are present, the normal vaginal environment is disturbed, and this can cause:

  • an increase in discharge,
  • a change in the consistency of discharge (it may become thin and watery)
  • discharge to turn white or grey in colour
  • discharge to produce an unpleasant smell, especially after sex.

It’s advisable to see a doctor if you notice any changes or your discharge is different to how it is normally.

Can BV be symptomless?

Yes. It is possible to have a level of bacteria in the vagina consistent with a BV ‘threshold’, but not have any symptoms. It is estimated that around half of women with bacterial vaginosis will not develop noticeable symptoms.

Is bacterial vaginosis an STI?

No. BV is not classed as an STI for a number of reasons.

Firstly, it is possible for the condition to be diagnosed in women who are not sexually active.

Secondly, there is no male equivalent of the condition and treating male partners with antibiotics does not prevent it from returning in their female partner.

Although BV is not an STI, sexual activity is thought to affect the likelihood of the condition occurring. BV has been found to be more common in females who have multiple sexual partners, and in those whose partners do not use condoms.

Can BV be mistaken for other conditions?

Yes, it is possible. There are other sexually transmitted infections that can cause similar symptoms to those produced by BV, such as gonorrhoea and trichomoniasis.

If you experience unusual vaginal discharge you should contact your doctor or attend your local genitourinary medicine (GUM) clinic. The staff may carry out a screening for other STIs, as well as checking for BV.

You can also order test kits for bacterial vaginosis online, if you think you may have the condition.

How can I treat BV symptoms?

Bacterial vaginosis doesn’t always require treatment. In some cases, symptoms may pass on their own.

Where symptoms are persistent or more severe, bacterial vaginosis can be treated with a course of antibiotics. The treatment can be prescribed as either a course of tablets, a single-dose tablet or a topical gel. The first-line treatment, where treatment is required, is metronidazole (also known by the brand name Flagyl).

You can read more on our page: How is BV treated?

Is it possible for BV to resolve without treatment?

Yes. BV can resolve on its own and some women who experience mild symptoms may not need treatment.

However, untreated BV can cause complications in pregnancy such as miscarriage, premature birth and a low birth weight; so if you are an expectant mother, it’s likely you will be offered treatment if you test positive for BV.

Page last reviewed:  18/10/2018