Decreased endometrial HOXA10 expression associated with use of the copper intrauterine device.

OBJECTIVE: To characterize human endometrial HOXA10 expression in patients using a copper intrauterine device (IUD).
DESIGN: Case-control study.
SETTING: Academic medical center. PATIENT(S): Women using copper IUDs. INTERVENTION(S): Immunohistochemical analysis of endometrial HOXA10 expression in biopsy samples obtained from 24 women using a copper Paraguard T380A as well as in samples obtained from 10 normal cycling women who were not using an IUD or hormonal contraceptives. MAIN OUTCOME MEASURE(S): Endometrial HOXA10 expression. RESULT(S): Endometrial HOXA10 expression was markedly decreased in the biopsy samples obtained from women using the IUD contraceptive when compared with controls. The mean H score for endometrial stromal cell HOXA10 expression in samples obtained from women using the Paraguard IUD was 0.21 compared with 2.2 in the control endometrial biopsy samples. Endometrial glandular expression of HOXA10 was absent in all IUD users. CONCLUSION(S): Decreased endometrial HOXA10 expression was apparent in women who use a copper IUD. Expression of HOXA10 is essential for endometrial receptivity. A novel mechanism of copper IUD action involves suppression of genes required for endometrial receptivity. The dramatic decrease of endometrial HOXA10 in response to IUD use may contribute to contraceptive efficacy.