Bacterial vaginosis is caused by an imbalance of the normal bacteria in the vagina, where protective bacteria like lactobacilli drop and other bacteria grow too much.

Common triggers

  • Douching or using scented vaginal products.
  • Sex, especially with a new or multiple partners, or unprotected sex.
  • An IUD, in some cases.
  • Natural shifts in the vaginal microbiome that can happen even without sex.

What it is not

BV is not always an STI , and you can get it even if you have not recently had sex. It also is not caused by toilet seats or swimming pools.

When to get checked

Typical signs include unusual discharge and a fishy smell, but some people have no symptoms. If symptoms are new, recurrent, or you’re pregnant, a clinician can confirm the cause and treat it appropriately.