Abstract: The single rod etonogestrel implant is a new implantable，highly effective，long-acting，reversible，progestin-only contraceptive. More advantages include its strong receptability，high safety，convenient insertion and remove，and long validity of 3 years. Compared with Norplant system of 6 roots，this single root implanont is inserted only one root，with significantly shortened times for insertion and remove. As a progestin-only contraceptive，this implant has a main side effect of menstrual disorder that users more likely discontinue，especially if the bleeding is prolonged. The other common adverse events includ acne，weight gain，and changes of bone density. In clinical practice，its contraindications should be cared，and more follow-up studies should be conducted.

Key words: Contraception, Progesterone, Etonogestrel, Menstruation disturbances, Acne vulgaris, Body mass index, Ovarian cysts