Implanon NXT 68 mg Sub-Dermal ImplantImplanon NXT contains 68 mg of etonogestrel, a progestin only contraceptive implant designed to provide up to 3 years of continuous pregnancy prevention. It is a small, flexible rod inserted just under the skin of the upper arm by a trained healthcare professional. It works primarily by inhibiting ovulation, thickening cervical mucus, and altering the endometrial lining, making it difficult for sperm to reach or fertilize an egg. ** Over 99 %