Contraception: hormone implant
What is a hormone implant?
A contraceptive hormone implant is a device that is surgically implanted beneath the skin. Implanon, which is available in Australia, is a small rod 40 mm long and 2 mm thick that is inserted into the upper arm.
How does it work?
Implanon contains etonogestrel, a type of synthetic progesterone, which is steadily released into the bloodstream. It works in a similar way to the ‘mini’ (progestogen-only) pill, by stopping the egg from being released from your ovaries (ovulation) and changing the cervical mucus so that sperm can’t penetrate it.
How effective is it?
In medical trials of Implanon, no pregnancies occurred in the women using it during a combined total of nearly 60,000 menstrual cycles.
What are the advantages?
Some of the advantages of contraceptive hormone implants are that they:
- work up to 3 years or until removed;
- allow fertility to return soon after removal;
- offer immediate protection against pregnancy;
- help protect against uterine cancer;
- do not interfere with intercourse; and
- do not affect bone density.
What are the disadvantages?
Some of the disadvantages of hormone implants are that they:
- may cause irregular bleeding or/and spotting;
- may produce side effects such as prolonged periods, light or no periods, breast tenderness, acne and weight gain;
- may cause localised bruising or soreness following insertion; and
- cannot be used by women with liver disease, breast cancer, unexplained uterine bleeding, or blood clots (deep vein thrombosis).
How is it used?
Implanon is inserted under the skin of the upper arm (your left arm if you are right-handed, and vice versa) between the first and fifth day of your menstrual cycle (day one is the first day of bleeding). The procedure is done under a local anaesthetic using a sterile disposable applicator. You will probably be asked to go back to your doctor after 3 months for a follow-up visit. The implant must be replaced by your doctor every 3 years. If you decide at any time that you want to try to get pregnant, the implant can be removed by your doctor and your periods should return quickly.
Last Reviewed: 01 May 2002
