Researchers do not know the cause of BV or how some women get it. We do know that the infection typically occurs in sexually active women. BV is linked to an imbalance of “good” and “harmful” bacteria that are normally found in a woman’s vagina. Having a new sex partner or multiple sex partners, as well as douching, can upset the balance of bacteria in the vagina. This places a woman at increased risk for getting BV.
We also do not know how sex contributes to BV. There is no research to show that treating a sex partner affects whether or not a woman gets BV. Having BV can increase your chances of getting other STDs.
BV rarely affects women who have never had sex.
You cannot get BV from toilet seats, bedding, or swimming pools.