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Contraceptive implant

The contraceptive implant is a small, flexible plastic rod containing the hormone progestogen, which is slowly released.

It works by stopping ovulation, thickening the mucus around the cervix, which makes it harder for sperm to get through, and making the lining of the womb thinner so that a fertilised egg cannot implant.

The implant is about 40mm long (about the size of a matchstick), and is put under the skin in your upper arm by a specially trained health professional (doctor or nurse).  Once it is put in, it protects against pregnancy for three years, or until you have it taken out.

Spend a bit of time looking here and finding out more about the implant. If you can’t find what you’re looking for here, or if you have more questions, you can get in touch with Ask Brook. Ask Brook is confidential. That means we won’t tell anyone you’ve contacted us unless we think you are in really serious danger.

The implant is a long acting reversible contraception (or LARC) method. LARC methods don’t rely on you remembering to take them, but they do need a trained doctor or nurse to administer or fit them for you.

​How do you use the implant?

The implant is placed just under the skin, in your upper arm. A doctor or nurse will give you a local anaesthetic injection, to numb this part of your arm before they put the implant in. It should only take a few minutes, and you won't need any stitches. The area may be slightly tender for a few days, but the doctor or nurse will put a small dressing on, to protect it and help stop any bruising.

If the implant is put in during the first five days of your period, it protects you against pregnancy straight away.

If it's put in on any other day of your menstrual cycle you will not be protected against pregnancy for the first seven days, so you'll need to use another method of contraception, (like condoms) for the first seven days.

​What is good about the implant?

  • Does not interrupt sex
  • You don’t have to remember to take a pill every day
  • Works for up to three years
  • No evidence that it causes additional weight gain
  • Fertility returns to normal once the implant is removed
  • Can be taken by some women who cannot use the contraception that contains oestrogen
  • The implant is not affected by vomiting, diarrhoea
  • May reduce period pain.

​What do I have to watch out for with the implant?

Periods may be irregular or stop altogether. 

​How effective is the implant?

The implant is over 99% effective.

What can make the implant less effective?

  • The implant must be replaced every three years
  • Some medicines can reduce the effectiveness of the patch, such as those used to treat epilepsy, HIV and TB and the complementary medicine St John's Wort. Commonly used antibiotics do not reduce the effectiveness of the pill, but it is always best to check with the doctor, nurse or pharmacist first
  • If at any time you cannot feel your implant or it appears to have changed shape, or you notice any skin changes or pain around the site of the implant, then visit a doctor or nurse at your nearest Brook service, sexual health clinic/GP, and use condoms until you know that your contraception is definitely protecting you again.