The effects of contraceptive hormones on the replication of Chlamydia trachomatis in human endometrial cells.

Several recent reports have documented a lower incidence of pelvic inflammatory disease (PID) among oral contraceptive users. The interpretation of this observation is difficult because the action of the contraceptive hormones may be directly by action on a specific host cell-parasite relationship, or indirectly via their action on other systems. In the present study we investigated the susceptibility of cultured human epithelial cells of the endometrium to infection by chlamydia and the influence of contraceptive steroids (ethinyl estradiol, mestranol and medroxyprogesterone acetate) upon replication of chlamydia in these cells. Forty-eight hours post-infection, elementary and reticulate bodies were observed in vacuoles of the infected endometrial cells by electron microscopy. Treatment of chlamydial-infected cells with contraceptive steroids in three different concentrations (10(-5)M, 10(-6)M and 10(-7)M) resulted in no effect on chlamydial replication, as examined by one-step growth curve. These results indicate that contraceptive hormones do not prevent chlamydial infection by direct effect on the replication of the agent.