Bacterial Vaginosis (Vaginal Overgrowth) Causes, Symptoms, Treatment

Bacterial vaginosis is a common vaginal infection which arises with overgrowth of bacteria in the vagina. It is not like with other vaginal infections where pathogenic microorganisms infiltrate the vagina and injure the tissue. Instead bacterial vaginosis arises when the various types of naturally-occurring bacteria (vaginal flora) multiply excessively. There are several species of bacteria in the vagina. These bacteria are usually harmless and necessary because it prevents other dangerous bacteria and yeasts from infecting the vagina. However the population of these bacteria need to be carefully controlled or it can pose a problem to the vagina.

Causes of Bacterial Vaginosis

The exact reason why the bacterial population grows out of control is unclear. It is not associated with hygiene. Excessive washing and vaginal douching can in fact promote overgrowth of bacteria as it disturbs certain aspects of the micro-environment in the vagina like the pH. Multiple species of anerobic bacteria proliferate in the vagina with bacterial vaginosis but there is a decline in the lactobacilli. It may be some factor that disturbs the lactobacilli which allows for the other types of bacteria to grow out of control.

Apart from douching, cigarette smoking and multiple sex partners may be other risk factors for developing bacterial vaginosis. However, with the latter it must be noted that bacterial vaginosis can even occur in girls or women who are not sexually active. Furthermore bacterial vaginosis is not a sexually transmitted infection. Hormonal changes with the menstrual cycle, pregnancy and menopause and the use of an intra-uterine device (IUD) may also contribute to the development of bacterial vaginosis.

Signs and Symptoms

The signs and symptoms of bacterial vaginosis are not signficantly different from other types of genitourinary infections in women. Most women with bacterial vaginosis, however, have no symptoms (asymptomatic). An abnormal vaginal discharge with a fishy odor are the main symptoms. Usually there are no other symptoms as is seen with other infections. Pain, burning, itching of the vagina and so on should raise the awareness about some other infection as these are not typically seen with bacterial vaginosis.

Developing bacterial vaginosis will increase the susceptibility to contract other infections, including sexually transmitted infections. The signs and symptoms of these infections may then be superimposed over the underlying bacterial vaginosis.


A medical history indicating the typical signs and symptoms and the absence of other infectious symptoms in conjunction with a pelvic examination may be sufficient for a diagnosis. However, it is advisable to follow up with further investigation like testing the pH of the vagina and examining the vaginal discharge under microscope.


Many cases of bacterial vaginosis may resolve spontaneously meaning that it eases without any treatment. Identifying any risk factors and preventing or removing it will allow the bacterial populations to return to normal. Drugs may be taken orally and/or applied topically. This includes the drugs metronidazole, tinidazole and clindamycin. Symptoms start to ease within the first 3 to 5 days of using antibiotics but the entire course needs to be completed for resolution of the condition. Although bacterial vaginosis can be successfully treated, it is not uncommon for it to recur usually within 3 to 6 months. Therefore women need to be aware of the risk factors and take the necessary measures to preventĀ  it.

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