Efficacy, safety and acceptability of the use of 68 mg etonogestrel contraceptive subdermal implant for up to 5 years compared with up to 3 years: a systematic review

Background: Prolonging the use of the etonogestrel (ENG) implant beyond the currently approved duration of 3 years could offer substantial benefits including improved accessibility, reduced need for replacements and overall lower healthcare costs. The purpose of this systematic review is to examine the current evidence regarding the effectiveness, safety and acceptability of the use of the ENG implant for up to 5 years. Methods: We searched PubMed, Embase, Scopus, Global Health, CINAHL, ClinicalTrials.gov, Global Index Medicus, Cochrane Central Register of Controlled Trials and International Clinical Trials Registry Platform from 1996 to 2024. Our study population included reproductive-aged women using the 68 mg single-rod ENG contraceptive implant. We included randomised controlled trials, retrospective and prospective cohort studies, case-control studies and conference presentations. Outcomes included those related to efficacy, safety and acceptability. The primary contraceptive efficacy outcome was Pearl Index between the third and fifth years of placement compared to that within 3 years. Results: We identified seven relevant studies. No pregnancies were noted among 860 participants within years 3–4 or among 306 participants within years 4–5. No important safety events were identified. Discontinuation of the implant due to bleeding was higher in the first 3 years of use (20.6%), compared with years 3–5 (5.4%). Due to the non-comparative nature of the studies and the overall low sample sizes of the studies, evidence certainty was deemed to be low or very low using the GRADE criteria. Conclusions: Current evidence, despite its low certainty, does not carry signals of potential concerns with regard to extended use, with potential for benefit.