Bacterial vaginosis is caused by an overgrowth of bacteria (bugs) that are normally only present in the vagina in small numbers. When these bacteria are present in large numbers they may cause symptoms such as an abnormal discharge or odour. Bacterial vaginosis is sometimes called non-specific vaginitis or Gardnerella vaginitis.
It is not clear whether bacterial vaginosis is a sexually transmitted infection and it isn’t known why some people with a vagina get it and some don’t. It often develops soon after intercourse with a new partner and can be associated with other sexually transmitted infections. It is possible that it may arise from bacteria transmitted on fingers or sex toys.
Bacterial vaginosis may cause an increase in normal vaginal secretions (fluid leaking from the vagina). There may be a strong odour from the vagina, and the smell may be worse after unprotected sex. Some people may not have any symptoms.
Bacterial vaginosis is easy to treat and does not lead to any serious health problems.
Bacterial vaginosis can be easily diagnosed by doing a vaginal swab test at your
local sexual health clinic. Results of this test will be available before you leave the appointment and you can be prescribed treatment.
Treatment of bacterial vaginosis is not required if there are no symptoms. Treatment is offered if you have symptoms or if you are about to have a gynaecological procedure (such as insertion of an IUD or termination of pregnancy) which could allow bacteria into the uterus.
Condoms used correctly every time you have sex from start to finish will provide some protection from bacterial vaginosis and offer good protection from many other sexually transmitted infections.
If you are diagnosed with bacterial vaginosis, it is recommended that sexual partners with a vagina are tested and treated too. Your nurse, doctor or sexual health clinic can help you deal with this situation, or read our section on How to tell a partner about STIs? Currently treatment of partners with a penis is not recommended as there’s insufficient evidence to show that it would be of benefit.