I found this article, hope it helps!
'Having BV when you're pregnant is associated with an increased risk of preterm birth and having a low-birth-weight baby, preterm premature rupture of the membranes (PPROM), <> and uterine infection after delivery. A few studies show a connection between BV and second-trimester miscarriage.
But the link between BV and pregnancy complications isn't perfectly clear. Experts don't yet know why only some women with BV end up delivering prematurely. They also don't know if BV directly causes complications such as PPROM or if women who are predisposed to other infections or problems that may lead to these complications are also more likely to have BV.
That said, many women with BV have perfectly normal pregnancies. And up to half of the cases of BV in pregnant women resolve on their own.
Having BV does make you more susceptible to certain sexually transmitted infections (STIs), such as chlamydia, gonorrhea, and HIV, if you're exposed to them. In women who aren't pregnant, BV has been linked to an increased risk of pelvic inflammatory disease (PID) and infections after gynecologic surgery. (It's possible to get PID during pregnancy, but it rarely happens.)'