Maldonado LY, et al. - Researchers examined a population of reproductive-aged Levonorgestrel Intrauterine System (LNG-IUS) users with normal regular menses prior to insertion in order to systematically determine the mean days of bleeding-only, spotting-only and bleeding and/or spotting experiences during the first year of use among these women. Searching 12 biomedical and scientific literature databases including MEDLINE and ClinicalTrials.gov., they identified 3,403 potentially relevant studies; of these, seven were included in this meta-analysis. Findings revealed that throughout the first year, a gradual decrease in combined menstrual bleeding and/or spotting days occurs, it decreased from 35.6 days (95% CI 32.2, 39.1) during the first 90-day interval to 19.1 (95% CI 16.6, 21.5), 14.2 (95% CI 11.7, 16.8), and 11.7 days (95% CI 9.7, 13.7) in the second, third, and fourth 90-day interval after LNG-IUS insertion, respectively. Throughout the first year, similar decreases in the measures for bleeding-only and spotting-only days were observed, with the greatest decreases occurring between the first and second intervals. This work thereby presents 90-day reference period measures that describe menstrual patterns for LNG-IUS users with normal regular menses prior to insertion during the first year of use. Findings afford broader generalizability and more detail than patterns described in the prescribing information. They suggest that improved informed selection and decreased discontinuation may be achieved with accurately establishing expectations with the LNG-IUS.