A pilot efficacy study with a single-rod contraceptive implant (Implanon® ) in 200 Indonesian women treated for ≤4 years

Abstract

In this 4-year open-label, noncomparative, single-center pilot efficacy study, the contraceptive efficacy, safety, bleeding pattern and acceptability of Implanon® was studied in 200 sexually active women of proven fertility in Indonesia. All subjects received the single-rod subdermal implant Implanon, which contains 68 mg etonogestrel (3-keto-desogestrel), with an initial release rate of 67 μg etonogestrel/day. Contraceptive efficacy was analyzed by calculation of the pregnancy rate, bleeding patterns were determined by the 90-day reference period method, and acceptability by the discontinuation rate. No in-treatment pregnancies were reported during 658.4 women-years of exposure, resulting in a Pearl Index of 0.0 (95% CI 0.0–0.6). The overall bleeding pattern was acceptable, with no discontinuations because of irregular bleeding. Incidence of irregular bleeding was highest during the first two reference periods and decreased thereafter. Amenorrhea was experienced by 7%–12% of subjects during years 1 and 2, by 5%–7% during year 3, and by 2%–5% during year 4, with one discontinuation because of amenorrhea. No clinically significant changes were reported for systolic and diastolic blood pressure, body mass index, and hemoglobin level. Three adverse experiences were related to treatment and resulted in discontinuation (two headaches and one dyspnea). One difficult implant removal was reported. In conclusion, this pilot efficacy study indicates that Implanon provides excellent contraceptive reliability and an acceptable bleeding pattern. Overall safety and acceptability are good, as suggested by the low incidence of adverse experiences and the low discontinuation rate.