Bacterial vaginosis is a polymicrobial, superficial vaginal infection involving a reduction in the amount of hydrogen-peroxide-producing Lactobacillus and an overgrowth of anaerobic and Gram-negative or Gram-variable bacteria.
Risk Factors
The current predictors of BV have been limited to race, sexual activity, socioeconomic status, and perhaps vaginal douching.
The reported prevalence of BV among pregnant women ranges from 10 percent to 35 percent, with higher rates occurring among African-American women, women of lower socioeconomic status, or women with prior sexually transmitted diseases.
Diagnosis
Two diagnostic tests are commonly used for BV. Amsel criteria, the test most commonly used in the clinical setting, involves assessing four clinical conditions, with the existence of three or more conditions corresponding to a diagnosis of BV.
The second diagnostic test involves a Gram stain of vaginal fluid and use of Nugent criteria to identify a case of BV. This method has been shown to have a high sensitivity and specificity compared with Amsel criteria (89 percent and 83 percent, respectively).