Contraceptive Implant

The contraceptive implant is a small flexible plastic tube which is placed under you skin in your arm. It measures 40 mm by 2 mm and prevents pregnancy for up to 3 years. In the UK, the implant used is called "Implanon" but is soon to be replaced by "Nexplanon" .

How effective is the contraceptive implant?

The contraceptive implant is over 99% effective if used correctly - this means that if 100 women would follow the methods during one year, less than one of them would be pregnant.

How does it work?

The implant releases progesterone which works in a few ways to prevent pregnancy:
  • the mucus in your cervix becomes thicker and hence prevents sperm from reaching your egg
  • the lining of your womb becomes thinner and therefore it is unlikely that a fertilised egg would be able to implant
  • your ovaries may stop releasing eggs

The implant can be inserted by a trained professional either by your GP or family planning clinic. It is a simple procedure carried out under local anaesthetic. The insertion and removal of the implant only lasts a few minutes and leave a 2 mm scar

Depending on your cycle, your GP will advise you when the implant will become effective - this could take up to 7 days. It lasts for 3 years - after this time, it can easily be removed and replaced with a new implant.


You don't need to remember to take the pill everyday. The implant does not interrupt sex unlike condoms. Your monthly period should become lighter and less painful. Some women do not have periods at all.

You can have the implant even if you are breastfeeding. It's useful if you cannot take contraception which contain oestrogen. It is not contra-indicated if you smoke.

The implant is absorbed through the skin so there should be less adverse-effects compared to taking an oral medication - for example, nausea. There may be some protection against pelvic inflammatory disease

The newer implant, Nexplanon, can be found by x-ray or ultrasound if it is difficult to locate.

Disadvantages and Risks

Contraindications to having the implant include pregnancy, liver disease, breast or gynaecological cancer, unexplained vaginal bleeding, or cardiovascular disease (e.g. heart attacks/strokes).

Irregular bleeding - you can experience spotting and erratic vaginal bleeding. This get better with time but in some cases, it becomes unacceptable and requires removal.

You may experience adverse-effects of the progesterone itself - such as headaches, weight gain, bloating, breast tenderness and mood changes.

During insertion, you may experience some bruising which will disappear in time. There is a small chance of a skin infection when the implant is inserted but this risk is reduced by using sterile technique.

It may be difficult to remove the implant, especially if it has moved location. There isn't any protection against STIs (sexually transmitted infections)

Further sources on information

You might find further reliable information on the Family Planning Association's website:
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