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Bacterial vaginosis (BV)

What is BV?

BV is the most common cause of abnormal discharge from the vagina.

Any woman can get BV, not just women who are sexually active.
The normal vagina contains a mixture of bacteria.

BV happens when there is an increase in certain types of bacteria, resulting in an overall imbalance.

It is not a sexually transmitted infection (STI).

How common is BV?

BV is common - any woman can get it, including women in same-sex relationships and women who have never had sex.

About one in 10 women will get BV at some point in their life. It is common in pregnant women.

How do I get BV?

The cause of BV is not fully understood - it is not caught from a sexual partner but sexual activity may play a part.

The vagina normally contains mostly 'good' bacteria (called lactobacilli), which help to cleanse the vagina, and fewer 'bad' bacteria (called anaerobes).

BV develops when there is an increase in the number of 'bad' bacteria. This changes the chemistry of the vaginal fluid. Although we do not understand why some women get BV and others don't, we do know that some activities can upset the normal balance of bacteria in the vagina and put women at increased risk.

These include:

  • having a new sex partner
  • smoking
  • douching (rinsing inside the vagina) or using vaginal washes or deodorants
  • having oral sex
  • having sex with multiple partners

You cannot catch BV from:

  • toilet seats
  • swimming pools or jacuzzis

What symptoms would I have with BV?

If you had BV, as well as an abnormal discharge from the vagina, common symptoms include an abnormal smell from the vagina, like a 'fishy' smell. Sometimes the 'fishy' smell is worse after sex.

BV does not cause itch, soreness or irritation.

How can I be tested?

BV can be diagnosed based on the symptoms you describe and some simple tests on the vaginal discharge.

How is BV treated?

BV is easily treated with antibiotics. It sometimes comes back and may need to be treated again.

What about my partner?

Your male partner does not need to be tested or treated.

Studies have shown that treating men does not prevent BV in their female partners.

Female partners of women with BV frequently have BV too.

Treatment of both partners may help to prevent BV coming back ('recurrences').

When can I have sex again?

BV is not sexually transmitted, so you do not need to avoid sex. However, some women find their symptoms clear up more quickly if they avoid sex.

What happens if my BV is left untreated?

For most women there are no complications from BV. It often clears up without treatment but if it persists you should go to your doctor or STI clinic.

How can I prevent against getting BV again?

To prevent against getting BV again, avoid anything that upsets the natural balance of bacteria in the vagina.

For example, don't:

  • douche (rinse inside your vagina)
  • bathe too frequently
  • use perfumed washes, bubble baths, antiseptic solutions or feminine wipes or washes


If you have had unprotected sex with a new partner, we recommend that you are tested for sexually transmitted infections (STIs).

BV in pregnancy

If you are pregnant and found to have BV that is bothering you, your doctor or nurse will speak to you about safe treatment. Treatment can be given even in the first trimester (the first 12 weeks).

In women who have had a miscarriage, premature or low birth weight baby, there is some evidence to suggest that BV may increase the risk of premature delivery in a subsequent pregnancy. For these women treatment is usually advised in pregnancy (preferably before 20 weeks).

Download the Bacterial Vaginosis (BV) leaflet here.