Contraceptive implants are a long-term birth control option for women. A contraceptive implant is a flexible plastic rod about the size of a matchstick that is placed under the skin of the upper arm. It is sold under the brandname Nexplanon. Nexplanon is radio opaque, which means it can be seen on X-ray, which is useful for checking the location of the implant.

It releases a low, steady dose of a progestational hormone to thicken cervical mucus and thin the lining of the uterus (endometrium). Contraceptive implants typically suppress ovulation as well.

The contraceptive implant isn't contraindicated for use in women who are overweight. However, it's possible the device may not be as effective in women with a body mass index (BMI) above 30.

Side effects of using the implant include:

  • redness or swelling at the site where the implant was inserted
  • signs of a stroke or blood clot
  • heart attack symptoms
  • increased blood pressure
  • depression
  • jaundice
  • swelling in your hands, ankles, or feet
  • vaginal itching or discharge
  • nausea, stomach pain
  • breast tenderness
  • flu-like symptoms, sore throat

Certain medications and herbal products may decrease the levels of progestin in your blood, which can decrease the contraceptive implant's effectiveness. Medications known to interact with the contraceptive implant include some seizure medications, certain sedatives, some HIV medications, as well as the herb St. John's wort. Talk with your doctor about your contraceptive options if you take any of these medications.