Intrauterine devices (IUD) provide effective contraception. The current study evaluates the concentration of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in the intrauterine fluid of postmenopausal women using an intrauterine delivery system releasing progesterone (IDS-P). Intrauterine fluid was obtained by lavage, and IL-6 and TNF-alpha were analyzed using an enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed with a one-way analysis of variance (ANOVA). Intrauterine fluid IL-6 levels were 33.6 vs 6.09 pg/sample IDS-P vs no IDS-P (p = 0.0301). Intrauterine TNF-alpha levels for women using the IDS-P were higher than in nonusers, but the differences did not reach statistical significance. IL-6 and TNF-alpha levels were increased in the intrauterine cavity of postmenopausal women with an IDS-P. These data suggest that secreted cytokines could be a potential mechanism of IUD contraceptive efficacy.
PIP: This paper examines the possible mechanism of action of a progesterone-releasing IUD (P-IUD) by evaluating the concentration of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in the intrauterine fluid of postmenopausal women using such a device. IL-6 and TNF-alpha were examined using an enzyme-linked immunosorbent assay (ELISA), while the intrauterine fluid was obtained by lavage. Intrauterine fluid IL-6 levels were 33.6 vs. 6.09 pg/sample for P-IUD vs. non-P-IUD users (p = 0.0301). Higher intrauterine TNF-alpha levels were observed in women using the P-IUD than in nonusers. The cells found in the intrauterine fluid of the P-IUD users were mostly histiocytes (macrophages) based on their morphologic characteristics. Increased IL-6 and TNF-alpha levels were found in the intrauterine cavity of postmenopausal women using a P-IUD. These results indicate that cytokines could play a significant role in the contraceptive mechanism of action of the IUD when used by premenopausal women.