Endometrial expression of glycodelin in women with levonorgestrel-releasing subdermal implants

Objective: To determine whether subdermal levonorgestrel implants induce endometrial expression of glycodelin. Design: Cross-sectional, blinded study. Setting: University clinic. Patient(s): One hundred and eight women with subdermal implants and 19 postmenopausal women. Intervention(s): Endometrial biopsies, curettages, and hysterectomies. Main Outcome Measure(s): Endometrial glycodelin expression was examined through immunohistochemistry, in situ hybridization, and morphologic endometrial dating. Result(s): Overall, 80% of the endometrial specimens obtained from women with subdermal levonorgestrel implants stained positive for glycodelin. Endometrial morphology of these women showed proliferative (71%), inactive/weakly proliferative (19%), menstrual or regenerating (6.5%), and other patterns (2.8%). Of these, 79%, 71%, 100%, and 100% were glycodelin positive, respectively. Nineteen specimens were obtained during the midcycle when glycodelin is not normally expressed: of these, 89% stained positive for glycodelin. Implant-related amenorrhea was associated with endometrial glycodelin expression in 58% of the women, whereas the endometrium specimens obtained from women with postmenopausal hypoestrogenic amenorrhea contained no detectable glycodelin. Conclusion(s): Subdermal levonorgestrel implant use is often associated with endometrial expression of glycodelin. Because glycodelin has been shown to inhibit sperm–egg binding, the induction of glycodelin may contribute to the contraceptive activity of the implant.