Contraception – Implanon

Implanon is small, thin, plastic rod, about the size of a matchstick (40 mm long and 2 mm wide), containing progesterone hormone. It is inserted underneath the woman’s skin, usually on the inside of her upper arm, using local anaesthetic. Implanon works in a similar way to progesterone injections, by stopping ovulation, thinning the lining of the uterus and thickening the mucous in the cervix. It lasts for three years, unless removed before this time and is more than 99% effective. About 0.1% of implants are inserted incorrectly, making them ineffective.

Side effects

Possibly irregular, light spotting, or frequent bleeding. A few women experience acne, headaches, weight gain, breast tenderness, dizziness, depression and/or loss of libido. There may be some bruising around the insertion site for a week or so afterwards.


Medsafe states that Implanon may be used during lactation.

Advantages of Implanon:

  • Set and forget. No pills or repeated injections.
  • After removal, fertility usually returns to normal within three to four weeks.

Disadvantages of implanon:

  • It needs to be inserted and removed by a doctor trained to do this. (Many GP’s can insert them.)
  • The effectiveness may wear off after two years for women who are overweight for their height.
  • If you don’t like the side effects, it will need to be removed early.

Find more information on contraception:

All information is recommended as a guide only. You should consult your doctor to find out what choice is right for you.

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