1. Lower-dose 13.5 mg and 19.5 mg levonorgestrel intrauterine contraceptive systems (IUDs) were found to be highly effective for up to 3 years.
2. Both devices were easy to insert and well tolerated by paras and nulliparas.
Evidence Rating Level: 1 (Excellent)
Study Rundown: This phase III clinical trial found that the newly developed, lower-hormone levonorgestrel IUDs were highly effective, relatively easy to insert, and well-tolerated for up to 3 years. These lower-dose IUDs have smaller frames and findings from Phase II trials suggest they are easier to insert than traditional IUDs.
Strengths of this study include large sample size and multi-site, multi-national cohort. limited in that it only included women with regular menstrual cycles, and thus could not evaluate efficacy with regards to abnormal uterine bleeding, a common indication for IUDs. Future studies might randomize women to the smaller, lower-dose versus Mirena IUD to assess contraceptive efficacy as well as treatment of abnormal uterine bleeding.
Click to read the study in Obstetrics & Gynecology
Click to read the study overview on clinicaltrials.gov
Relevant Reading: Recent developments in the clinical use of the levonorgestrel-releasing intrauterine system
In-Depth [randomized controlled trial]: In this Phase III single-blinded trial, researchers from 138 centers around the globe randomized 2,885 women to either a 13.5 mg (n=1,426) or 19.5 mg (n=1,445) levonorgestrel intrauterine contraceptive device (IUD) for three years. The primary outcome was pregnancy rate (number of pregnancies/100 women-years). Secondary outcomes included bleeding patterns, ease of placement, safety, continuation and user satisfaction.
Over a 3-year study period, women with the IUD were less likely to become pregnant: 0.33 (95% CI=0.16-0.60) for the 13.5mg IUD and 0.31 (CI=0.15-0.57) for the 19.5 mg IUD. Cumulative failure rates were 0.9% for the 13.5 mg and 1.0% for the 19.5 mg system. Overall, placement was successful in over 99.5%, placement was rated as easy by physicians in 90% of patients and only 8% of women rated severe pain associated with placement. Discontinuation rates were 21.9% and 19.1% in the 13.5 mg and 19.5 mg groups, respectively.
By Maren Shapiro and Leah Hawkins, MD, MPH
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