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 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.

Contraceptive implants are radio opaque and can be seen on X-rays — useful for identifying the location of an implant.

Contraceptive implants offer effective, long-term contraception. Among various benefits, a contraceptive implant:

• Can be removed at any time, followed by a quick return to fertility
• Eliminates the need to interrupt sex for contraception
• Contains no estrogen

Contraceptive implants aren't appropriate for everyone, however. Your health care provider may discourage use of a contraceptive implant if you:

• Are allergic to any components of the implant
• Have had serious blood clots, a heart attack or a stroke
• Have liver tumors or liver disease
• Have known or suspected breast cancer or a history of breast cancer
• Have undiagnosed abnormal genital bleeding

Although the label for etonogestrel (Nexplanon) says it shouldn't be used by women with a history of blood clots, it isn't clear whether the contraceptive implant affects the risk of blood clots. The warning comes from studies of combination birth control pills that contain the same progestin as is used in the contraceptive implant.

Talk to your health care provider if you have any risk factors for blood clots, including a history of blood clots in your legs or a prior diagnosis of a blood clot in your lungs (pulmonary embolus).

In addition, tell your health care provider if you have a history of:

• An allergic reaction to anesthetics or antiseptics
• Depression
• Diabetes
• Gallbladder disease
• High blood pressure
• High cholesterol or high triglycerides
• Seizures or epilepsy

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.

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.

The contraceptive implant doesn't offer protection from sexually transmitted infections.

Fewer than 1 out of 100 women who use the contraceptive implant for one year will get pregnant. If you do conceive while using a contraceptive implant, there's a higher chance that the pregnancy will be ectopic — when the fertilized egg implants outside the uterus, usually in a fallopian tube. However, because a contraceptive implant prevents most pregnancies, women who use it are at lower risk of having an ectopic pregnancy than are other sexually active women who aren't using contraception.

Side effects associated with contraceptive implants include:

• Abdominal or back pain
• An increased risk of noncancerous ovarian cysts
• Changes in vaginal bleeding patterns, including absence of menstruation (amenorrhea)
• Decreased sex drive
• Dizziness
• Headaches
• Mild insulin resistance
• Mood swings and depression
• Nausea or upset stomach
• Potential interaction with other medications
• Sore breasts
• Vaginal inflammation or dryness
• Weight gain

Your health care provider will evaluate your overall health before inserting the contraceptive implant. He or she will determine the appropriate timing for the insertion of the implant based on your menstrual cycle and your previous birth control method. You may need to take a pregnancy test and use a nonhormonal backup method of contraception for one week.

A backup method of contraception may not be necessary if you previously:

• Used no contraception and have the contraceptive implant inserted during the first five days of your menstrual cycle, even if you're still bleeding
• Used combination birth control pills, a vaginal ring or a patch for birth control and have the contraceptive implant inserted within seven days of the start of your hormone-free period
• Used the minipill and have the contraceptive implant inserted while taking active pills
• Used a contraceptive injection and have the contraceptive implant inserted the day your next injection is due
• Used another contraceptive implant or an intrauterine device (IUD) and have the etonogestrel implant (Nexplanon) inserted the day your previous device is removed

You can have a contraceptive implant inserted during a visit to your health care provider's office. The actual procedure takes just a minute or so, though preparation will take a bit longer.

During the procedure

You'll lie on your back with the arm that will receive the implant bent at the elbow and positioned near your head. Your health care provider will locate a groove between the biceps and triceps muscles on the inner side of your upper arm. He or she will inject a local anesthetic and then use an applicator to insert the device just beneath your skin. Inserting the device too deeply makes removal difficult.

After the procedure

Your health care provider will feel your arm to confirm the presence of the implant and have you do the same. If necessary, he or she may also use an ultrasound or X-ray to confirm that the device has been inserted.

Your health care provider will cover the insertion site with a small bandage. He or she may also apply a pressure bandage to minimize bruising. You can remove the pressure bandage in 24 hours, but keep the small bandage clean and in place for three to five days.

It's common to experience some degree of bruising, pain, scarring or bleeding at the insertion site.

Contact your health care provider if you develop:

• Breast lumps
• Heavy, prolonged vaginal bleeding
• Signs or symptoms of a blood clot in your leg, such as persistent pain and swelling in your calf
• Signs or symptoms of jaundice, such as yellowing of the skin or whites of the eyes
• Signs or symptoms of an infection at the insertion site, such as tenderness, redness, swelling or discharge
• Signs or symptoms of pregnancy at any time after the contraceptive implant is inserted

Removal

The contraceptive implant can prevent pregnancy for up to three years. It must be removed and replaced at the three-year point to continue offering protection from unintended pregnancy.

Your health care provider may recommend removing the contraceptive implant earlier if you develop:

• Migraine with aura
• Heart disease or stroke
• Uncontrolled high blood pressure
• Jaundice
• Significant depression

To remove the device, your health care provider will inject a local anesthetic in your arm beneath the implant. He or she will make a small incision in your skin and will push the implant toward the incision until the tip is visible and can be grasped with forceps.

Your health care provider will then pull out the implant, close the incision and apply a pressure bandage. Contraceptive implant removal typically takes less than five minutes.

If you choose, a new device can be implanted as soon as the original device is removed. Be prepared to use another type of contraception right away if you don't have a new device inserted.

A contraceptive implant can prevent pregnancy for up to three years. It must be removed and replaced every three years to continue prevent pregnancy.