A 12-month multicenter, randomized study comparing the levonorgestrel intrauterine system with the etonogestrel subdermal implant.

Objective: To compare the levonorgestrel intrauterine system (LNG-IUS 8), which has an average levonorgestrel release rate of ∼8 μg/24 hours during the first year (total levonorgestrel content 13.5 mg; Jaydess/Skyla), with the etonogestrel (ENG) subdermal implant (total content, 68 mg) with regard to the 12-month discontinuation rate (primary outcome).

Design: Randomized, open-label, phase III study.

Setting: Thirty-eight centers in six European countries.

Patient(s): Study population of 766 healthy nulliparous and parous women aged 18-35 years.

Intervention(s): The LNG-IUS 8 or the ENG implant.

Main Outcome Measure(s): Discontinuation rate, by treatment group, at Month 12.

Result(s): The 12-month discontinuation rates were 19.6% and 26.8% in the LNG-IUS 8 and ENG implant groups, respectively. The -7.2% difference was statistically significant (95% confidence interval -13.2%, -1.2%). Fewer women in the LNG-IUS 8 group than in the ENG implant group discontinued because of increased bleeding (3.2% vs. 11.3%) or adverse events (14.3% vs. 21.8%). At 12 months, more women in the LNG-IUS 8 group than in the ENG implant group were "very/somewhat satisfied" with their bleeding pattern (60.9% vs. 33.6%) and reported a preference to use their study treatment after study completion (70.1% vs. 58.5%).

Conclusion(s): The LNG-IUS 8 was associated with a significantly lower 12-month discontinuation rate compared with the ENG implant; mainly because ENG implant users frequently discontinued due to increased bleeding. More LNG-IUS 8 users than ENG implant users reported being "very/somewhat satisfied" with their bleeding pattern, and reported a preference to continue using their study treatment after the study.

Clinical Trial Registration Number: NCT01397097.