Endometrial histology following 1 year of a continuous daily regimen of levonorgestrel 90 μg/ethinyl estradiol 20 μg

Objective: The objective of this study was to evaluate the effect of a continuous daily regimen of levonorgestrel (LNG) 90 mu g/ethinyl estradiol (EE) 20 mu g on endometrial histology. Methods: This was a substudy of a large phase 3 trial conducted in six sites in North America. Healthy and sexually active women aged between 18 and 49 years took LNG 90 mu g/EE 20 pg daily for I year. Results from endometrial biopsies performed at pretreatment baseline and those after at least 6 months of treatment were compared. Results: Of the 146 participants, 93 had a baseline biopsy and completed at least six pill packs. Before treatment, 56 subjects (60%) had an endometrial biopsy with findings classified as "weakly proliferative or proliferative." During the last on-therapy visit, 48 subjects (52%) had an endometrium, categorized as "other," which included primarily an inactive or benign endometrium (n = 42). No hyperplasia or malignancy was observed during the study. Conclusion: The results of a 1-year continuous regimen of LNG 90 mu g/EE 20 mu g were shown to have a good endometrial safety profile. (c) 2007 Elsevier Inc. All rights reserved.