Objective
To evaluate the expression of biomarkers of implantation, glycodelin A (GdA), osteopontin (OPN), lysophosphatidic acid receptor 3 (LPA3), and HOXA10, in eutopic endometrium of women with and without endometriosis. Design: Prospective observational study. Setting: Clinical research center. Patient(s): Twenty-four women with endometriosis and 23 healthy volunteers of similar age. Intervention(s): Secretory phase endometrial biopsy. Main outcome measure(s): Expression of immunohistochemical staining intensity and localization of GdA, OPN, LPA3, and HOXA10 in eutopic endometrium. Result(s): Endometrial GdA expression was significantly reduced in patients after cycle day 22. The endometrium from women with endometriosis also showed decreased expression of OPN in the late secretory phase and LPA3 and HOXA10 expression in the midsecretory and late secretory phases.