Compare the Efficacy of Dienogest and the Levonorgestrel Intrauterine System in Women with Adenomyosis

Purpose The goal of this study was to examine the efficacy and safety of the levonorgestrel intrauterine system (LNG-IUS) versus dienogest (DNG) in female subjects with symptomatic uterine adenomyosis. Methods This study enrolled 117 women with symptomatic adenomyosis who visited our hospital from May 1, 2019, to June 30, 2022. Participants were randomized to either the LNG-IUS group (n = 48) or the DNG group (n = 79) in an as-controlled clinical trial for 36 months. Visual analog scale (VAS) scores, uterine volume, endometrial thickness, serum carcinoma antigen 125 level, estradiol, follicle-stimulating hormone, luteinizing hormone, and side effects were assessed to compare the efficacy of LNG-IUS and DNG. Findings The VAS pain score was significantly decreased in both groups after 3 months of treatment. Three months later, patients receiving DNG reported significantly lower VAS scores compared with those treated with LNG- IUS (P < 0.05). Compared with LNG-IUS, DNG effectively controlled uterine volume growth after 12 months of treatment but neither significantly reduced uterine volume. During the treatment period, endometrial thickness in both groups was maintained at 0.4 to 0.7 cm. Implications Both DNG and LNG-IUS significantly improved adenomyosis-associated pain after 3 months of treatment. Compared with LNG-IUS, DNG was shown to continuously relieve the symptoms of pain and effectively control the growth of uterine volume.