What are contraceptive implants?

Updated: Jan 29, 2018
  • Author: Megan Brady Shannon, MD; Chief Editor: Michel E Rivlin, MD  more...
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The contraceptive implant is a popular form of long-acting reversible contraception (LARC). Norplant, the first contraceptive implant, became available in 1983 [1] but was later removed from the market owing to patient dissatisfaction with adverse effects that ultimately led to several lawsuits against the manufacturer. It was also difficult to remove. [2]

The currently available implant, Nexplanon, is a rod that contains the progestin etonogestrel and is intended for subdermal implantation in the non-dominant arm. It is the second-generation of the device; the first-generation was called Implanon. The currently available device differs from its first-generation counterpart in that the implant itself is radiopaque and its applicator design is improved so as to prevent placement deeper than the intended subdermal location.

The advantage of an implantable form of contraception is that it provides effective long-term contraception that does not depend on the recipient’s daily compliance. The implant has become a popular choice among adolescents and young women, and is appropriate for both nulliparous or parous women. [3]

The most recent generation of implantable devices is the most effective form of birth control available and can usually be inserted by trained practitioners in less than one minute. [4, 5, 6, 7] The pregnancy rate with the implant is 0.05%, which is slightly lower than the levonorgestrel intrauterine device (0.2%) and the copper intrauterine device (0.6%). [8, 9]

A release rate of 25-30 µg/day of etonogestrel is required to suppress ovulation. With this device, the initial rate of release is 60-70 µg/day, which slowly decreases over time, to about 30 µg/day. Maximum serum levels are attained the fourth day after insertion, on average.

After removal of the implant, etonogestrel serum levels become undetectable within one week. [1, 6, 10]

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