If you read about the options for putting something in your arm the actual side effects are scary. Norplant is just creepy I remember my step-day (an OB/GYN) bringing home surgery videos to learn how to put them in and it looked nasty. Another option is a one implant in the arm but still there can be scars and it can move. You have to check it often to make sure that it doesn't move around.
Yeah, but the shit lasts 5 years, iirc.