Comparing the Efficacy of Levonorgestrel Intrauterine Device and Oral Levonorgestrel for Emergency Contraception: A Systematic Review and Meta-Analysis

Abstract

Emergency contraception (EC) is critical for preventing unintended pregnancies. Oral levonorgestrel (LNG) is the standard FDA-approved EC method, while the levonorgestrel intrauterine device (LNG-IUD) is an emerging alternative that provides immediate EC and long-term contraception, although not FDA approved for EC right now. This study evaluates the efficacy of LNG-IUD compared to oral LNG for EC through a systematic review and meta-analysis. A systematic review and meta-analysis were conducted according to PRISMA 2020 guidelines. PubMed, Scopus, Medline, and ClinicalTrials.gov were searched through December 16, 2024. Five studies, including 920 participants, met population, intervention, comparison, outcome, and setting (PICOS) criteria, focusing on reproductive-age women using LNG-IUD or oral LNG as EC. Risk of bias was assessed using the Mixed Methods Appraisal Tool (MMAT), and a random-effects model was applied due to heterogeneity across studies. When indirectly compared with oral LNG, the LNG-IUD demonstrated a natural log of the odds risk ratio (ORR) of -0.51 (95% CI: -3.86 to 2.83, p=0.77), suggesting a slightly lower risk of pregnancy. However, the wide confidence interval and high p value likely reflect the small sample size and limited number of studies, reducing the ability to detect significant differences. This review found no statistically significant difference in efficacy between LNG-IUD and oral LNG for EC likely attributed to the limited data. Nonetheless, LNG-IUD may offer comparable or potentially greater efficacy, with the additional benefit of long-term contraception. Further large-scale, direct comparative studies are warranted to confirm efficacy and expand EC options for women.