The birth control implant is one of the most effective forms of contraception, with a pregnancy rate of well under 1% per year when in place and inserted correctly, meaning it is over 99% effective.

What the implant is

  • The implant is a small, flexible rod placed under the skin of your upper arm that releases a progestin hormone (etonogestrel or levonorgestrel).
  • It works mainly by stopping ovulation, thickening cervical mucus, and thinning the uterine lining to prevent pregnancy.

How effective is it?

  • Large studies and reviews report failure rates around 0–0.8 pregnancies per 100 women per year (≤0.8%), which translates to more than 99% effectiveness.
  • In some long‑term follow‑up data (including millions of cycles), no in‑treatment pregnancies were found while the implant was in place and within its approved time window, again confirming >99% protection.

How long it lasts

  • Most commonly used implants (like Nexplanon/etonogestrel) are approved for 3 years, though research shows high effectiveness can extend up to 5 years in many users.
  • Fertility generally returns quickly after removal, often within a few weeks to a few months.

Factors that matter

  • Correct placement : It must be inserted properly in the arm by a trained clinician; rare failures are often linked to incorrect insertion or unrecognized expulsion.
  • Body weight and medications : Some older data suggested slightly lower effectiveness with higher body mass index and with certain enzyme‑inducing medications (like some epilepsy medicines), so providers may discuss this if relevant.

Side effects and real‑world use

  • Common side effects include irregular bleeding, lighter or heavier periods, or no periods at all; these bleeding changes are the main reason many people stop using it.
  • Despite side effects, continuation rates at 1 year are generally high (around three‑quarters or more), and satisfaction is often good compared with daily methods like the pill.

How it compares to other methods

  • The implant is at least as effective as hormonal IUDs and generally more effective than pills, patches, or rings in typical everyday use because it removes the need to remember a daily or weekly dose.
  • Unlike condoms, its effectiveness does not depend on what happens in the moment, but it does not protect against sexually transmitted infections, so condoms are still recommended for STI protection.

TL;DR: The birth control implant is a long‑acting, reversible method that is over 99% effective at preventing pregnancy, lasts several years, and works without you having to remember anything daily, but irregular bleeding is common and can be bothersome for some users.

Information gathered from public forums or data available on the internet and portrayed here.