Histopathological Insights into Treatment Failure with the Levonorgestrel-Releasing Intrauterine System in Women with Heavy Menstrual Bleeding: A Retrospective Study

The levonorgestrel-releasing intrauterine system (LNG-IUS) is an established first-line therapy for heavy menstrual bleeding (HMB), effectively reducing blood loss and improving quality of life in most women; however, some patients fail to achieve adequate response. This retrospective study, conducted at BARC Hospital, Mumbai, from January 2017 to March 2020, aimed to evaluate histopathological findings among women with HMB who did not respond to LNG-IUS therapy. A total of 88 women were treated, of whom 26 (29.5%) were classified as non-responders. Endometrial biopsy findings revealed proliferative endometrium in 65.4%, disordered proliferative endometrium in 19.2%, and secretory endometrium in 15.4% of cases. Among nine non-responders who underwent hysterectomy, adenomyosis was the most common finding (44.4%), followed by adenomyosis with leiomyoma (33.3%), endometrial polyp (11.1%), and leiomyoma (11.1%). These results indicate that treatment failure is predominantly associated with structural uterine abnormalities, particularly adenomyosis. The study highlights the need for thorough pre-insertion evaluation, including clinical and imaging assessment, to detect underlying pathology and improve patient selection. Individualised management based on uterine morphology and symptom profile may enhance therapeutic success and reduce unnecessary delays in achieving symptom control.