Contraceptive implants are small plastic rods containing contraceptive medication that are inserted under the skin of a woman's non-dominant arm. The ingredients in the contraceptive implant include the hormones levonorgestrel or etonogestrel. The implant will take effect after 24 hours and is effective for 3-5 years or longer (depending on the type). Once the contraceptive implant is implanted, women do not need to use any other contraceptive method.