Sergison JE, et al. - Researchers systematically calculated the amenorrhea measures for a general population of Levonorgestrel Intrauterine System (LNG-IUS) users, to assess the validity of existing amenorrhea prevalence estimates and provide 90-day interval point estimates for the first year of use. Outcomes revealed that amenorrhea is experienced by nearly 20% of LNG-IUS users during at least one 90-day interval by the first-year post-insertion. In line with the product labeling, this composite estimate demonstrates that amenorrhea is not experienced by most users during the first year. Accurate summary measures gained in this work may facilitate counseling and informed method selection.