Use of etonogestrel implant beyond approved duration: prolonged contraceptive effectiveness.

Background: The subdermal etonogestrel contraceptive implant has a current approved duration of 3 years. There is, however, recent and strong evidence of its effectiveness for 2 additional years during which no pregnancies were documented.
Case: We report a case of a 28-year-old woman who had an etonogestrel implant inserted 4 years earlier and wished to get pregnant. The implant was, however, deep in the triceps muscle and could not easily be removed. Her serum levels of etonogestrel remained positive even 6 years after insertion. As infertility investigation revealed endometriosis and bilateral tubal obstruction she was referred for assisted reproduction. Despite obtaining oocytes during an ovarian stimulation cycle, the endometrium was never above 4 mm, precluding embryo transfer. It was decided to remove the implant in order to improve endometrial conditions, after which the patient achieved pregnancy.
Conclusion: This case report suggests that the etonogestrel implant is effective for even longer than the most recent studies have shown.