Please note: This archive was last updated in 2005.

RHO archives : Topics : Contraceptive Methods

Implants

Overview

Contraceptive implants consist of hormone-filled capsules that are inserted under the skin in a woman's upper arm. The first contraceptive implant system developed was the Norplant system, which consists of six thin, flexible capsules made of silicone. Each capsule is 2.4 mm in diameter and 34 mm in length and contains 36 mg of the progestin levonorgestrel. Norplant-2 (also known as Jadelle) is a two-rod system that has been approved in various countries for 5 years (Sivin 2002). Several other implant systems are currently being tested. Implants are a safe and effective method of reversible, long-term contraception for most women. They do not interfere with intercourse and are effective within 24 hours after insertion (IPPF 2000).

Data from a recent five-year, international, post-marketing surveillance study of nearly 8,000 Norplant users confirmed the safety and efficacy of this method (Meirik et al. 2001).

For more information, please see the references in the Annotated Bibliography or the section on new implants on the Contraceptive Research and Development page.

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Characteristics of contraceptive implants (Norplant)

Effectiveness

0.1% to 1.0% failure rate for soft-capsule implants during first year of use; 1.6% failure rate over five years of use.

Age limitations

No restrictions on use for women age 16 and over.

Parity limitations

No restrictions on use.

Mode of action

Primarily by thickening cervical mucus, thereby preventing sperm penetration, and also by inhibiting ovulation.

Effect on STI risk

Not protective.

Drug interaction

Certain antiseizure medications (barbiturates, carbamazepine, phenytoin, primadone) and antibiotics (Rifampin and Griseofulvin) may reduce the contraceptive effect of implants.

Duration of use

Norplant implants are effective for five years. Most women can use implants safely throughout their reproductive years (if the woman is satisfied with the method and has no problems with it).

Return to fertility

Immediately upon removal.

Also see Hormonal Contraception, IUDs, and HIV Risk.

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