What causes BV?
A healthy vagina contains bacteria called lactobacilli, which produce lactic acid. The lactic acid helps to keep the vagina slightly acidic, which stops other bacteria growing there.
BV develops when the natural balance of bacteria in your vagina is upset, and there are not enough of the lactobacilli present to keep the vagina acidic. The result can be that other bacteria start to grow.
The causes of this change in numbers aren’t understood, although there are factors that can put you at a higher risk of developing BV. These include:
BV is also more common in black women than in other ethnic groups.
Other things that can sometimes trigger BV include an operation on the vagina, douching, or putting non-sterile objects into the vagina.
Why some women develop BV isn’t fully understood.