What Is a Birth Control Implant and How Does It Work?

The birth control implant is a small, matchstick-sized rod that goes underneath the skin. Also called Nexplanon, arm implant birth control releases two hormones — progesterone and etonogestrel — to prevent pregnancy. The birth control implant may last 3 to 5 years (ask your doctor) and is 99% effective.

Disclaimer: The following was written for informational purposes. It is not medical advice. Wondering what kind of contraception to use? Speak with your gynecologist.

What Is a Birth Control Implant (Nexplanon)?

It’s a small, matchstick-sized plastic rod that is medically inserted into a woman’s arm just underneath the skin to prevent pregnancy. More specifically, arm implant birth control is a form of hormonal birth control — meaning that it uses notably two hormones (progesterone and etonogestrel), which prevent pregnancy.

Always remember that the birth control implant does not protect against STIs (sexually transmitted diseases).

What Does It Do, Exactly?

The main active hormone in Nexplanon, the birth control implant, is etonogestrel. Etonogestrel prevents the ovaries from releasing eggs while thickening cervical mucus, thus preventing pregnancy in 99% of cases.

How Effective Is the Birth Control Implant?

Nexplanon is 99% effective, making it one of the more effective types of contraception. IUDs — intra-uterine devices — are also 99% effective. Here’s how the birth control arm implant compares to other forms of contraception.

Birth Control Implant vs Hormonal and Intra-Uterine Effectiveness

• Implant (Nexplanon): over 99% effective
• IUD (hormonal and non-hormonal): over 99% effective
• Birth control pills: 93% effective with typical use*
• Shot (Depo-Provera): 96% effective
• Patch: 93% effective
• Vaginal ring: 93% effective with typical use*

Keep in mind that plan b is not a form of birth control.

The arm implant, the pill, the shot, the patch, a hormonal IUD and a vaginal ring are all types of hormonal birth control. Hormonal birth control contains hormones naturally produced by the female body — progesterone, and estrogen, for example — to stop the release of the egg. This means that the sperm has nothing to fertilize.

Note that they are two types of IUD: hormonal and copper. They have similar effectiveness rates (more than 99%).

Related article: "10 Period Sex Tips"

Arm Implant vs Barrier Contraception Effectiveness

Barrier contraception methods create a physical barrier between the sperm and the egg. They do not release hormones.

• Birth control implant (Nexplanon): over 99% effective
• Male condom: 87% effective with typical use*
• Female condom: 79% effective with typical use*
• Diaphragm (cervical cap) with spermicide: 83% with typical use*

Understanding Perfect vs Typical Use

For many forms of contraception, there is a significant difference between perfect use and typical use. This is because there is a significant risk of human error with forms of birth control like the pill, condoms, and diaphragms. It’s easier than you think to forget to take your pill or to put a condom on incorrectly.

By contrast, the implant is inserted by a doctor and lasts for 3 to 5 years. Though it does not protect against STIs, it does provide an easy form of contraception that doesn’t require the user to remember to take or do anything.

How Long Does the Birth Control Implant Last?

Typically, it lasts up between 3-5 years. Check with your gynecologist for more information.

How Much Doe the Birth Control Implant Cost?

The short answer is: it depends. The list price for Nexplanon is a little under $1,000, though it may be partially or completely subsidized by health insurance, including Medicaid, and other government programs. Check with your gynecologist or local Planned Parenthood office for more information.

Birth Control Implant Possible Side Effects

• Changes in menstrual cycle: This may mean longer, shorter, or irregular periods or spotting. Talk to your gynecologist if you experience heavy menstrual bleeding, long periods, or have concerns.
• Headaches
• Acne
• Mood changes
• Weight gain

As always, if you have questions or concerns about birth control implant side effects, speak with your doctor. If you are experiencing any of these side effects, speak with a medical professional.

How Is the Birth Control Implant Inserted?

Nexplanon is always inserted by a medical professional.

• The upper arm is numbed using an anesthetic.
• The implant — a match-sized plastic piece — is inserted. The process may feel like an injection.
• It can be worn for between 3-5 years. After that point, it must be removed and replaced by a medical doctor in order to remain effective.
• The implant will not be effective after it’s effective by date and the user will not be protected from pregnancy after it is removed.

Pro Tip: Try a period tracker to learn more about your symptoms and flow.