CHARLESTON, S.C. — Chlamydia trachomatis may play more of a role in abnormal uterine bleeding than previously recognized, Miklos Toth, M.D., reported at the annual meeting of the Infectious Diseases Society for Obstetrics and Gynecology.
Although many women with abnormal uterine bleeding have endometritis that is associated with silent pelvic inflammatory disease (PID), and C. trachomatis is the most important pathogen in the etiology of silent PID, the histologic features of chlamydia endometritis and the relationship between C. trachomatis and abnormal uterine bleeding have not been well described, said Dr. Toth of Lenox Hill Hospital, New York.
To better define these factors, he studied 92 archived endometrial biopsy specimens from premenopausal women with abnormal uterine bleeding and/or endometritis. Of these, 48% tested positive for C. trachomatis by species-specific monoclonal antibody against the major outer membrane protein (MOMP).
The specimens also were tested for histopathology associated with inflammation, and associations were noted between C. trachomatis (defined as a positive MOMP-specific stain) and higher counts of plasma cells, macrophages, and lymphocytic foci, Dr. Toth said.
The strongest predictor of C. trachomatis, as indicated by the receiver operating characteristic curve (area under the curve = 0.88), was macrophage count. The mean number of macrophages in the C. trachomatis-positive specimens was 619, which was significantly greater than the macrophage count of 11 in the negative specimens.
The currently accepted histologic definition of silent PID (five or fewer polymorphonuclear leukocytes and one or fewer plasma cells per 40×) was not indicative of C. trachomatis in this study.
These findings suggest that C. trachomatis is underestimated in women with abnormal uterine bleeding and that currently used histologic criteria for silent PID will miss many cases of C. trachomatis infection. Women with missed infection who become pregnant may have increased risk for miscarriage, Dr. Toth said.
The findings also suggest that macrophage counts are a very promising tool for detecting C. trachomatis in the endometrium, he noted.