Posted in Web Bacterial vaginosis | Health topics A to Z | CKS | NICE January 23, 2021 Bacterial vaginosis (BV) is characterized by an overgrowth of predominantly anaerobic organisms and a loss of lactobacilli. The vagina loses its normal acidity, and its pH increases to greater than 4.5. https://cks.nice.org.uk/topics/bacterial-vaginosis/