The efficacy of intrauterine devices for emergency contraception and beyond: a systematic review update

Background: The copper intrauterine device (IUD) is a very effective form of emergency contraception. The failure rate is about 0.1%. IUDs are also very cost-effective when used as long acting-reversible contraception (LARC). The purpose of this review is to attempt to confirm these findings. Methods: The references for this study were generated by entering the terms “intrauterine device” and “emergency contraception” in Medline, PubMed, Popline, Global Health and ClinicalTrials.gov. Chinese references were obtained from the Wanfang database. For the emergency contraception study, articles with a defined population who were followed up until outcome were eligible. Women who were adequately followed for at least 6 months were included in the long term arm of the study. Results: There were 18 (of 228) studies which met our selection criteria and were conducted in five countries, between August 2011 and January 2018. There were 1720 insertions of seven types of copper IUD with a failure rate of 0.12%. The maximum time from intercourse to IUD insertion was 14 days. The discontinuation rate at 12 months was over 20% in the long term studies. Conclusion: There are now a combined total of 8550 reported insertions from two reviews with 8 pregnancies and a failure rate of 0.093%. Copper IUDs remain an effective form of emergency contraception, for which they are under-promoted. The major limitation of the studies is the lack of data relating unprotected intercourse to the day of the cycle.