Causes
A healthy vagina normally contains many microorganisms; some of the common ones are Lactobacillus crispatus and Lactobacillus jensenii. Lactobacilli, particularly hydrogen peroxide-producing species, appear to help prevent other vaginal microorganisms from multiplying to a level where they cause symptoms. The microorganisms involved in BV are very diverse, but include Gardnerella vaginalis, Mobiluncus, Bacteroides, and Mycoplasma. A change in normal bacterial flora including the reduction of Lactobacilli, which may be due to the use of antibiotics or pH imbalance, allows more resistant bacteria to gain a foothold and multiply.
Although BV can be associated with sexual activity, there is no clear evidence of sexual transmission. It is possible for sexually inactive persons to get infected with bacterial vaginosis. Rather, BV is a disordering of the chemical and biological balance of the normal flora. Recent research is exploring the link between sexual partner treatment and eradication of recurrent cases of BV. Pregnant women and women with sexually transmitted infections are especially at risk for getting this infection. Bacterial vaginosis may sometimes affect women after menopause. A 2005 study by researchers at Ghent University in Belgium showed that subclinical iron deficiency (anemia) was a strong predictor of bacterial vaginosis in pregnant women. A longitudinal study published in February 2006 in the American Journal of Obstetrics and Gynecology showed a link between psychosocial stress and bacterial vaginosis independent of other risk factors.
Read more about this topic: Bacterial Vaginosis