Bacterial vaginosis (BV) occurs when there is an imbalance of the healthy bacteria in the vagina. What causes an imbalance? Washing inside the vagina is the most preventable cause. The vagina is completely self-cleaning and washing inside the vaginal canal is actually harmful. So the best piece of advice I have for preventing BV may be surprising: wash LESS!
If you find BV is triggered by sex, using a condom for all vaginal sex may help. This is because semen can mess up that perfect vaginal balance, but BV only occurs in vaginas, not penises so your partner doesn’t need treatment.
BV can be passed vagina to vagina so lesbians or other queer couples may need to get treated at the same time (as you would with any contagious STI).
For some, BV can be hormonal — they’ll find it tends to come and go around the same time each month. This is trickier to manage, but talk to your GP or attend a women’s health centre to make a preventative treatment plan.