OBJECTIVES: LNG-IUS-12 is a low-dose hormonal intrauterine contraceptive system for up to 3 years of use. This analysis aimed to evaluate the cost-effectiveness of LNG-IUS-12 in comparison to short-acting reversible contraceptive (SARC) methods in a cohort of young women in the United States (US) from a third-party payer’s perspective. METHODS: A state-transition model was developed to assess cost-effectiveness of LNG-IUS-12 versus SARC methods over 3 years in 1000 women aged 20-29 years, the age group accounting for over half of all abortions in the US. SARC methods comprise of oral contraceptives, ring, patch and injections – methods commonly used by this cohort. The model consisted of three mutually exclusive health states: initial method, unplanned pregnancy (UP) and subsequent method. Subsequent method is represented by a mixed market-weighted contraceptive ‘basket’. Failure and discontinuation rates were based on published literature. Unit costs were taken from standard US databases. Cost and effectiveness metrics for SARC were weighted using market share data. The key model output was cost per UP avoided. One-way sensitivity analyses (OWSA) and probabilistic sensitivity analyses (PSA) were performed. RESULTS: LNG-IUS-12 dominated SARC, resulting in fewer UP (65.26 vs. 278.97) and lower total costs ($1,274,295USD vs. $1,822,836USD, a 43% saving) over 3 years. The costs associated with subsequent method used by women who initiated LNG-IUS-12 were lower ($107,587USD vs. $230,024USD) due to lower failure and discontinuation rates of LNG-IUS-12. OWSA results were insensitive to variation in key input parameters. PSA results indicate a high probability of dominance as all iterations were less costly and more effective. CONCLUSIONS: From a third-party payer perspective, LNG-IUS-12 is a more cost-effective contraceptive option than SARC. Therefore, women switching from current SARC use to LNG-IUS-12 are likely to generate cost savings to third-party healthcare payers, driven principally by decreased UP-related expenditures and long-term savings in contraceptive costs.