A condition where the vaginal microbiome shifts away from being dominated by Lactobacillus (protective bacteria) toward a more diverse mix of other bacteria, including species like Gardnerella.
BV is typically diagnosed using scoring systems (such as the Nugent score) that assess the balance of bacterial types in a vaginal sample, rather than the presence of a single organism.
It’s common, often has no symptoms, and has been linked to infertility, miscarriage, and lower IVF success rates in some studies, although results are not always consistent.