Bacterial vaginosis and risk of pelvic inflammatory disease

Bacterial vaginosis commonly is found in women with pelvic inflammatory disease (PID), but it is unclear whether bacterial vaginosis leads to incident PID.

Women (n = 1,179) from 5 U.S. centers were evaluated for a median of 3 years. Every 6-12 months, vaginal swabs were obtained for gram stain and culture of microflora. A vaginal microflora gram stain score of 7-10 was categorized as bacterial vaginosis. Pelvic inflammatory disease was diagnosed by presence of either histologic endometritis or pelvic pain and tenderness plus one of the following: oral temperature greater than 38.3 degrees C; sedimentation rate greater than 15 mm/hour; white blood count greater than 10,000; or lower genital tract detection of leukorrhea, mucopus, or Neisseria gonorrhoeae or Chlamydia trachomatis.

After adjustment for relevant demographic and lifestyle factors, baseline bacterial vaginosis was not associated with the development of PID (adjusted hazard ratio 0.89, 95% confidence interval 0.55-1.45). Carriage of bacterial vaginosis in the previous 6 months before a diagnosis (adjusted risk ratio 1.31, 95% confidence interval 0.71-2.42) also was not significantly associated with PID. Similarly, neither absence of hydrogen peroxide-producing Lactobacillus nor high levels of Gardnerella vaginalis significantly increased the risk of PID. Dense growth of pigmented, anaerobic gram-negative rods in the 6 months before diagnosis did significantly increase a woman's risk of PID (P =.04). One subgroup of women, women with 2 or more recent sexual partners, demonstrated associations among bacterial vaginosis, Gardnerella vaginalis, anaerobic gram-negative rods, and PID.

In this cohort of high-risk women, after adjustment for confounding factors, we found no overall increased risk of developing incident PID among women with bacterial vaginosis.

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