Clinical efficacy and safety of indomethacin-gyneFix IUD combined with a levonorgestrel-releasing intrauterine system in patients with adenomyosis and different uterine cavity depths

Background: Adenomyosis is commonly associated with dysmenorrhea and heavy menstrual bleeding. Although the levonorgestrel-releasing intrauterine system (Mirena, LNG-IUS) is recommended as a first-line conservative treatment, device displacement or expulsion remains a major limitation, especially in patients with enlarged uteri or deep uterine cavities. Objectives: To evaluate the clinical efficacy and safety of the Indomethacin-GyneFix IUD (GyneFix IUD) combined with LNG-IUS in patients with adenomyosis and to assess whether uterine cavity depth influences device stability. Methods: In this single-center prospective randomized controlled trial, 270 patients with adenomyosis were randomly assigned in a 1:1:1 ratio to the GyneFix IUD + LNG-IUS group, the ring IUD + LNG-IUS group, or the LNG-IUS-alone group (90 patients each). The primary endpoint was the rate of device displacement/expulsion at 6 months. Secondary endpoints included changes in visual analogue scale (VAS) scores, pictorial blood loss assessment chart (PBAC) scores, uterine volume, hemoglobin (Hb), serum CA125, adverse events and patient acceptance. Subgroup analysis was performed according to uterine cavity depth (?9cm vs. >9 cm). Results: At 6 months, the displacement/expulsion rate was significantly lower in the GyneFix IUD + LNG-IUS group (2.22%) than in the ring IUD + LNG-IUS group (10.00%) and the LNG-IUS-alone group (18.89%) (?2=13.468, P<0.001). All three groups showed significant improvement in dysmenorrhea, menstrual blood loss, Hb and CA125 compared with baseline, without significant between-group differences (all P>0.05). Adverse event rates were comparable among groups (all P>0.05). Patient willingness to choose the same treatment again (95.12%) and willingness to recommend it (90.24%) were significantly higher in the GyneFix IUD + LNG-IUS group. In patients with uterine cavity depth >9 cm, the stability advantage of this strategy was more pronounced. Conclusion: GyneFix IUD combined with LNG-IUS significantly reduces device displacement/expulsion in adenomyosis, particularly in patients with deeper uterine cavities, while maintaining comparable symptom relief and safety. It may represent a more stable and acceptable long-term conservative treatment option.