Birth Control Implant "The Implant" (Nexplanon) – The implant is a small, flexible, match-stick sized rod that is inserted just under the skin of the underside of a client’s upper arm by a clinician. Nexplanon is so small that most people cannot see it once it is inserted. The device releases a hormone that keeps the ovaries from releasing an egg and thickens the cervical mucus. This thickened mucus helps block the sperm from getting to the egg. Nexplanon is effective for up to three years and fertility returns upon removal of the implant.