Help & Advice

What is Bacterial Vaginosis?

Bacterial vaginosis (BV) is a condition where the bacteria that normally live in the vagina become disrupted leading to an unusual vaginal discharge.

It is normal for a woman to have vaginal discharge at any point in time and the discharge will change in consistency and colour throughout the menstrual cycle. Most women who have BV do not have any symptoms and so are unaware that they have it. Other women who develop BV may notice that their discharge develops a strong fishy odour (especially after sexual intercourse). It may also become more watery or is a different colour than usual.

BV is not a sexually transmitted infection and so it cannot be passed on during sex but having sex may make the condition worse and you are more likely to develop BV if you are sexually active.

If a woman has BV, symptoms can develop at any time and it is something that can recur in the future even if it gets better or is treated.

Approximately half of women do not have any symptoms so it is very important for women with an unusual vaginal discharge who are sexually active to have a sexual health screening after each new sexual partner. They should also be aware of what is normal for them so that they can spot any changes as soon as they arise.

Regular use of condoms, good sexual health awareness and not sharing sex toys (such as vibrators and dildos) are good ways to reduce the transmission of any sexual infection.

There is some evidence to show that women who have sex with other women can pass BV on to each other, although it is not clear how this happens. There is no evidence to show that women with BV can pass it on to men but it is always very important to practice safe sex.

What are the Causes of BV?

BV is caused by a disruption in the balance of lactobacilli (healthy bacteria) that live in the vagina. Lactobacilli make the vagina slightly acidic and this prevents certain other bacteria from growing there keeping it clean and healthy. Women with BV have less lactobacilli. Use of soaps, shower gels, deodorants and perfumes (even those that are specifically designed for use on the vagina) wipe out the lactobacilli and allow the BV-causing bacteria to multiply. Women with coils and those who 'douche' (wash the vagina out with water) are also more likely to develop BV.

BV and giving birth

If a woman develops BV in pregnancy there is a very small increased risk of developing pregnancy-related problems such as ectopic pregnancy, miscarriage and premature labour. If you are pregnant and think you may have BV you must tell your midwife, GP or Sexual Health Doctor.

How is BV Diagnosed?

BV can be diagnosed by swab tests. These tests are quick and easy to perform. Diagnosing BV early is important and minimises the risks of complications developing. BV can be diagnosed at a GUM (genitourinary medicine) clinic or via your GP.

How is BV Treated?

BV is easily treated with a course of metronidazole, an oral antibiotic. Treatment is highly successful if the antibiotics are taken exactly as instructed. Please note that antibiotics do not protect from future infection. It is therefore possible to become re-infected with BV whilst taking the metronidazole and in this instance you must seek medical attention to confirm re-infection and must take the antibiotics again.

Please note that it is possible to contract more than one infection at any one time so practicing safe sex is really important.