Comparison of the Efficacy and Safety of Mifepristone and Dienogest in the Treatment of Symptomatic Adenomyosis: A Retrospective Cohort Study

Objective This study aims to systematically compare the short-term efficacy and safety differences between daily oral 2 mg Dienogest (DNG) and daily oral 10 mg Mifepristone (MIF) in the treatment of patients with symptomatic adenomyosis, focusing on the impact of both drugs on uterine volume, clinical symptoms (dysmenorrhea, menorrhagia), and adverse events, providing a basis for individualized medication treatment. Methods A single-center retrospective cohort study was conducted, including 83 patients diagnosed with adenomyosis who received drug treatment from May 1, 2023, to May 1, 2025. The patients were divided into the Mifepristone group (35 cases, 10 mg/day) and the Dienogest group (48 cases, 2 mg/day), with treatment lasting for 3 months. The uterine volume, endometrial thickness, amenorrhea rate, hemoglobin, CA125 levels, and adverse events were compared between the two groups before and after treatment. Statistical analysis was performed using SPSS 27.0, with P < 0.05 considered statistically significant. Results After 3 months of treatment, the median uterine volume in the MIF group significantly decreased from 151.56 cm³ to 104.07 cm³ (P < 0.01), with a reduction value of 32.29 cm³, significantly higher than the 8.103 cm³ in the DNG group (P < 0.01). The amenorrhea rate in the MIF group (97.1%) was significantly higher than that in the DNG group (58.3%). Both groups showed a significant increase in hemoglobin and a significant decrease in CA125 (both P < 0.01). The DNG group showed a significant thinning of endometrial thickness (P < 0.01), while the MIF group did not show significant changes (P > 0.05). The overall adverse reaction rate in the MIF group (45.71%) was lower than that in the DNG group (75%). Conclusion In a 3-month pre-treatment period, Mifepristone significantly outperformed Dienogest in reducing uterine volume and improving the amenorrhea rate in patients with adenomyosis, while also exhibiting better tolerance.