P077Pilot study on a novel, alternative subdermal scapular insertion site for the etonogestrel contraceptive implant

Abstract

<h3>Objectives</h3> To assess the pharmacokinetics and pharmacodynamics of the etonogestrel (ENG) contraceptive implant when inserted at an alternative scapular site. <h3>Methods</h3> We conducted a pilot study of healthy, reproductive-aged women who underwent subdermal insertion of an ENG implant over the inferior edge of the non-dominant scapula (scapular insertion). We measured serum ENG levels over one year at nine time points. Participants completed questionnaires on insertion site and bleeding side effects. We collected photographs and video recordings of insertion and removal techniques. <h3>Results</h3> We enrolled five participants (as prespecified): Their median age was 26.0 (range, 19.6–30.3) and their median BMI was 25.0 kg/m2 (range, 22.0–28.0). Among five scapular implant users, all serum ENG concentrations remained >90 pg/mL during the first year of use and demonstrated bioequivalence with published data for arm insertion of ENG implant at all time points. The mean serum ENG level was 511.7±168.2 pg/mL at one week and 130.3± 19.1 pg/mL at 12 months. During the first week of insertion, four of five participants noted insertion site pain with a median pain score of 2 (range, 1–3), but all noted resolution by week two. Participants reported bleeding patterns similar to standard ENG implant use. At the end of the study, all participants were satisfied with the implant and would recommend scapular insertion to a friend. <h3>Conclusions</h3> Scapular insertion of the ENG contraceptive implant has bioequivalent pharmacokinetics to arm insertion over one year of use. This novel, alternative site was well tolerated and demonstrated similar bleeding side effects to standard arm insertion.