Implanon (etonogestrel implant) is a small non-biodegradable implant that is inserted under your sub-dermis (second layer of the skin) by a qualified physician, Implanon should not be left in place for more than 3 years. Not for use in suspected or known pregnancy or if you are breastfeeding a baby, recent or recurrent deep vein thrombosis, liver disease, known or suspected carcinoma with sex-hormones sensitivity pattern, or any type of abnormal vaginal bleeding. The most common side effect is a change in bleeding frequency and intensity. Tell your doctor of any medical condition and discuss any risk factor that can predispose you to blood clot formation and breast cancer.