Contraceptive Implant

Compare the treatment options for contraception. A Brief Decision Aid.

What is the contraceptive implant?

A contraceptive implant is a small tube that is put under the skin. It contains a progestogen hormone. Nexplanon® is the only one prescribed in the UK at present. This is a tube 40 mm long and 2 mm wide (about the size of a hair grip).

From October 2010 Nexplanon® replaced Implanon®, which was used in the UK before this time.

Nexplanon® is different to Implanon® in two ways:

  • It is easier to insert than Implanon®.
  • It contains barium, which means that it will show up on an X-ray. This may be useful to locate it if it cannot be felt in the future.

How does the contraceptive implant work?

The progestogen hormone in the implant is released into the bloodstream at a slow, steady rate. The progestogen works mainly by stopping ovulation (the release of the egg from the ovary). It also thickens the mucus which forms a mucous plug in the cervix. This stops sperm getting through to the womb (uterus) to fertilise an egg. It also makes the lining of the uterus thinner. This means that if an egg were to fertilise, it would not be likely to be able to attach to the uterus.

How effective is the contraceptive implant?

Less than 1 woman in 1,000 using the implant will become pregnant each year. When no contraception is used, more than 80 in 100 sexually active women become pregnant within one year.

What are the advantages of using a contraceptive implant?

  • You do not have to remember to take a pill every day.
  • You only have to think about contraception every three years.
  • It does not interfere with sex.
  • It can be used when breast-feeding.
  • Period pain is usually less.
  • It can used by some women who cannot take pills that contain oestrogen.
  • It may help to protect against pelvic infection as the mucous plug in the cervix may help to prevent bacteria from travelling into the uterus.

What are the disadvantages of using a contraceptive implant?

The release of progestogen will usually cause changes to the pattern of periods. During the first year, it is common to have irregular bleeding. Sometimes periods are heavier and longer than before. They usually settle back into a regular pattern after the first year, but may remain irregular. In some women the periods become infrequent and light, or even stop all together. One in five women with the implant have no bleeding. However, one in two have irregular bleeding which can be a nuisance.

If you do develop irregular bleeding after having the implant inserted then you should inform your doctor. Irregular bleeding can occasionally be due to another reason – for example, an infection, which may need to be treated.

Who cannot have a contraceptive implant?

Your doctor or family planning nurse will discuss any current and past diseases. Some diseases may mean you cannot use progestogen-based contraceptives such as Nexplanon®, but this is uncommon.

Are there any side-effects with the contraceptive implant?

As with all hormonal contraceptives, some women report side-effects such as breast discomfort, fluid retention and increase in acne. Some women actually find an improvement in their acne though. If side-effects do occur they tend to develop in the first few months only. They often go after 3-6 months if the implant remains in. As with all small cuts to the skin, there is a slight risk of a wound infection. The possible effects on periods are mentioned above.

There is no evidence that women with an implant in put on weight. It is also not associated with an altered sex drive or mood changes. It does not cause any thinning of your bones.

How is the contraceptive implant put under the skin?

  • It is put in the inner side of the upper arm.
  • It is usually first inserted within five days of a period starting, to ensure that you are not pregnant. It is effective immediately.
  • An injection of local anaesthetic is used to numb the skin. A small cut is made and the implant placed under the skin. The wound is dressed and will soon heal just like any other small cut.
  • The area around the implant may be bruised and sore for a few days, but this soon goes.

Do I need to be seen again after the implant is inserted?

You do not need to be routinely seen by your doctor or nurse after having your implant inserted. However, you can return at any time to discuss any problems. You should see your doctor or nurse if the following occur:

  • You cannot feel your implant.
  • Your implant appears to have changed shape.
  • You notice any change in your skin or have any pain in the area around the implant.
  • You become pregnant.

When is the contraceptive implant taken out?

A replacement is needed every three years if you wish to continue with this form of contraception. It requires a small operation under local anaesthetic to remove it and put in a new one.

The implant can be taken out at any time if you request removal. It loses its effect immediately after being removed. So, if required, use other forms of contraception afterwards and for seven days before it is removed. This is because sperm can survive for up to seven days after sex.

There is no delay in your fertility returning after the implant is removed.

Do other medicines interfere with the contraceptive implant?

Some prescribed medicines may interfere with the progestogen (mainly some used for epilepsy and tuberculosis). Tell the doctor or pharmacist that you have a progestogen implant if you are prescribed another medicine. It is unlikely that a medicine bought without the need for a prescription will interfere. If in doubt, ask the pharmacist.

Further information

Your GP, practice nurse and pharmacist are good sources of information if you have any queries.

The fpa (formerly the family planning association) also provides information and advice.
Helpline: 0845 310 1334 or visit their website www.fpa.org.uk

References and Disclaimer | Provide feedback


  • Long-acting reversible contraception, NICE Clinical guideline (October 2005); (the effective and appropriate use of long-acting reversible contraception)
  • Progestogen-only Implants, Faculty of Sexual and Reproductive Healthcare (2009)
  • Power J, French R, Cowan F; Subdermal implantable contraceptives versus other forms of reversible contraceptives or other implants as effective methods of preventing pregnancy. Cochrane Database Syst Rev. 2007 Jul 18;(3):CD001326. [abstract]
  • Nexplanon®, CEU Statement, Faculty of Sexual and Reproductive Healthcare, 2010


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