Curriculum · Gynecology / Women's Health / Infertility / Perinatal Care / Birth Spacing
Bacterial vaginosis
What it is
Bacterial vaginosis is the commonest cause of vaginal discharge, and it is not an STD. The organism is Gardnerella vaginalis, and Mycoplasma hominis is named with it. What lies under it is a loss: normal lactobacilli, which are hydrogen peroxide producing, are reduced, so the pH rises. That is why the pH is one of the tests and not a side note. Put the other way, it is an overgrowth of predominately anaerobic organisms such as Gardnerella vaginalis, which leads to a fall in the lactic acid producing aerobic lactobacilli and so to a raised vaginal pH.
Causes and risk
Risk factors are sexually active, douching, and smoking. Prevention is by condom, or by an estrogen containing OCP. It is itself a risk factor, and this is where it is asked: pelvic inflammatory disease lists bacterial vaginosis among its risk factors, next to Mirena, multiple sexual partners, oral contraception and STIs, and so does postpartum endometritis, next to Cesarean section, prolonged labour, prolonged rupture of membrane and vaginal examination. It is not a sexually transmitted infection, yet it is seen almost exclusively in sexually active women.