Variability of bacterial vaginosis over 6- to 12-month intervals.

Objectives: To examine variability in bacterial vaginosis (BV) over 6- to 12-month intervals.

Study Design: One thousand one hundred ninety-three women were followed for a median of 3 years with serial vaginal swab Gram stains for BV. Discrete time hazard models were fit to identify independent risk factors for BV.

Results: Women with BV at study entry were categorized as having normal flora at the next visit 20% of the time, and women with normal flora at study entry were categorized as having BV at the next visit 20% of the time. Among women with initially normal flora, factors associated with BV were black race, lower education, a history of BV, a history of chlamydial/gonococcal cervicitis, and lack of monogamy.

Conclusion: About one fifth of women with normal flora develop BV over a given 6- to 12-month interval, and the modifiable risk factors of cervicitis and lack of monogamy contribute to the development of BV.