Bacterial vaginosis

Bacterial vaginosis is the most common form of vaginitis in women of childbearing age, accounting for 40%-50% of cases. It is characterized by a major change in the normal balance of vaginal bacterial flora, usually the Lactobacillus species, to anaerobic species. This change in bacterial flora leads to a rise in vaginal pH and the production of malodorous amines responsible for the classic clinical manifestations of this condition.

Although bacterial vaginosis is not considered an STI, the risk factors are the same. However, this condition also occurs in women who have never had vaginal intercourse.

A thin, yellow-green or grey, homogenous, malodorous (fishy-smelling) vaginal discharge is common. Bacterial vaginosis alone does not generally cause symptoms associated with inflammation (erythema or edema) nor does it cause itching, pain, a burning sensation or difficulty urinating. Urination problems suggest co-infection with another pathogen. Surprisingly, 50%-70% of women with bacterial vaginosis have no symptoms at all.

The presence of bacterial vaginosis can have other health consequences. In pregnant women, there is an increased risk of premature labour and delivery. Other gynecological complications may also be associated. An imbalance in the vaginal bacterial flora also increases the chances of being affected by other infections such as herpes, gonorrhea, chlamydia and trichomoniasis.

At least three of the following four criteria must be present to formulate a diagnosis of bacterial vaginosis during a medical examination.

• Fluid, homogenous, yellow-green or grey vaginal discharge
• Vaginal pH above 4.5
• Presence of an amine (fishy) odour after the addition of KOH to vaginal discharge
• Vaginal flora compatible with bacterial vaginosis (e.g., Nugent score ≥7)

Priority is given to oral antibiotics for women who are not pregnant. To limit the systemic effects of oral treatment, a topical protocol is preferable for pregnant women.