The diagnosis of bacterial vaginosis (BV) has become common during the last 10 years, with about 97,000 women per year being seen in GUM clinics, and an unknown number being treated elsewhere.

Gardnerella occurs when normal vaginal bacteria is displaced by anaerobic bacteria – mainly by a bacterium called Gardnerella vaginalis. The cause is unknown and is often found on routine testing of women who do not have any symptoms or signs of the condition. The normal pH level is usually around 3 but in anaerobic vaginosis the pH level rises to 5 or 6. This is the opposite of the situation that occurs in Thrush when the pH goes down to 2.

Although it is more common in women who are sexually active, it is not considered a sexually transmitted infection.

BV is a common cause of vaginal discharge. The discharge is usually whitish or greyish or sometimes yellowish, and tends to have an off-putting ‘fishy’ odour.

Unlike the discharges caused by thrush or trichomonas, it’s not usually associated with soreness, discomfort or itching.

It’s uncertain if BV is transmitted sexually, especially as there’s no equivalent condition in males.

Treatment an antibiotic called Metronidazole tablets is given as a single large dose or as a twice a day dosage for one week. Recurrences may be prevented by using a gel that lowers the vaginal pH.