Implanon is a birth control (contraceptive) implant for women. Implanon is a flexible plastic rod about the size of a matchstick that is placed under the skin of the upper arm. It releases a low, steady dose of a progestational hormone to thicken cervical mucus and thin the lining of the uterus (endometrium). Implanon typically suppresses ovulation as well.

A newer version of Implanon also is available. It's called Nexplanon and it's radio opaque. This means it can be seen on X-ray, which is useful for checking the location of the implant. Implanon and Nexplanon are the only contraceptive implants with Food and Drug Administration (FDA) approval available in the U.S.

Jan. 21, 2012