The cause of BV is not understood. It can develop when something, like sexual contact, disrupts the balance between the good bacteria that protect the vagina from infection and the harmful bacteria that don't. It is not clear what role sexual activity plays in the development of BV, but BV is more common among women who have had vaginal sex. But BV is not always from sexual contact. We do know that certain things can upset the normal balance of bacteria in the vagina and put you more at risk for BV, for example:

· Having a new sex partner or multiple sex partners

· Douching

· Using an intrauterine device (IUD) for birth control

· Not using a condom

One common myth is that you can get BV from toilet seats, bedding, swimming pools, or from touching objects around you, this is not true.