The expression of cyclooxygenase-2 and vascular endothelial growth factor in the endometrium during the peri-implantation period in women with and without polyps

Objective: This prospective study was designed to determine whether the expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) in the endometrial tissue obtained from the peri-implantation period of women with endometrial polyp (EP) differs from that of control subjects without a polyp. Methods: Endometrial samples were collected from 30 patients with EP and 30 control subjects without EP, in the mid-secretory phase. The expression of COX-2 and VEGF in the endometrium was examined with the use of immunohistochemistry. Results: COX-2 and VEGF were predominantly expressed in endometrial glands. The expression of COX-2 and VEGF in the endometrium obtained from women with EP was lower than that of control subjects. Conclusion: The reduced expression of COX-2 and VEGF in the endometrium of women with EP may account for the association between EP and infertility.