Bleeding patterns of women with heavy menstrual bleeding or dysmenorrhoea using the levonorgestrel-releasing intrauterine system: results from a real-world observational study in Japan (J-MIRAI)

To collect real-world safety and clinical outcome data on the levonorgestrel-releasing intrauterine system (LNG-IUS) for functional/organic heavy menstrual bleeding (HMB) and dysmenorrhoea in Japanese women (J-MIRAI). In this prospective, multicentre, single-cohort, open-label, post-authorisation study, we assessed menstrual blood loss after LNG-IUS insertion by changes from baseline in pictorial blood loss assessment chart (PBAC) scores. Scores for the menorrhagia multi-attribute scale (MMAS) were collected for 12 months to assess quality of life. We included 47 patients with complete PBAC score and patient diary data. The median PBAC score before LNG-IUS insertion was 159.0, which decreased significantly to 6.0 at 12 months post-insertion; for patients with adenomyosis (n = 20), PBAC score decreased from 174.5 pre-insertion to 19.5 at 12 months. The number of patient-reported bleeding days was correlated with PBAC score ≥5. The proportion of women with prolonged bleeding decreased from 85.7% to 34.6% by the study’s end. Some women reported no bleeding after the first 90-day reference period. The mean MMAS overall score significantly increased from 50.50 before insertion to 88.67 at 12 months. Japanese women with functional/organic HMB experienced substantial reductions in bleeding symptoms and improvements in quality of life after 12-month use of the LNG-IUS.