A Narrative Review and Risk-Stratification Framework for Preventing LNG-IUS Expulsion in Adenomyosis

Levonorgestrel-releasing intrauterine system (LNG-IUS) expulsion rates are markedly elevated (15-37.5%) in patients with adenomyosis compared to those with normal uteri (3-10%), significantly compromising treatment efficacy and adherence. Existing evidence on risk factor mitigation is fragmented, lacking a structured management framework. This narrative review synthesizes current literature to identify key determinants of expulsion-including uterine enlargement, intracavitary lesions, and insertion techniques-and evaluates preventive strategies such as GnRH-agonist pretreatment and imaging-guided placement. Its primary aim is to propose a novel, three-tiered risk-stratification model that tailors management (conventional, augmented, or advanced fixation approaches) to individual patient profiles based on anatomical, procedural, and clinical factors. This structured approach seeks to optimize LNG-IUS retention and resource allocation. Prospective validation through randomized controlled trials remains essential to establish evidence-based, personalized protocols.