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Intrauterine Device (IUD)

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What is an IUD?

An Intrauterine Device or IUD, is a small, T-shaped plastic and copper method of contraception that is placed inside your uterus (womb) by a doctor or nurse. It is often referred to as the contraceptive coil or copper coil.

How does an intrauterine device work?

The IUD releases copper into your womb which will stop you getting pregnant. The copper changes the mucus within your cervix making it more difficult for any sperm to reach your egg and survive. It also works to stop a fertilised egg implanting itself. After you have had an IUD fitted it can protect against pregnancy for between 5 to 10 years.

If you're over 40 years old you can have an IUD fitted and it can be left in place until you reach the menopause or you no longer need to use a method of contraception. The device begins to work as soon as it has been put in, and it can be put in at any time during your menstrual cycle.

How effective is an IUD?

When an IUD has been inserted correctly by a doctor or nurse they are more than 99% effective*. The IUD doesn’t use hormones so you won’t experience any normal hormonal side effects such as acne or headaches. Having an IUD fitted will not protect you from catching an STI, you will also need to use a barrier method such as condoms during sexual intercourse.

Do IUDs stop your period?

With IUDs your periods can be heavier, longer and more painful during the first three to six months after your IUD has been fitted. You may also notice spotting or bleeding between your periods. However your periods should settle down and improve after the initial few months.

What are the pros and cons of coil contraception?

Before having the contraceptive coil fitted you may want to consider whether it is right for you as an effective method of contraception. You may want to chat about your choice with friends or family to see what experiences anyone you know has had with the copper coil.


  • It works straight away once it is fitted
  • Most women can use it
  • It doesn’t use hormones so you won’t have any hormonal side effects such as headaches
  • You can use an IUD if you are breastfeeding
  • It can stop you from getting pregnant for between 5 to 10 years, depending on the type
  • It won’t interrupt sex
  • As soon as you decide to have it removed, you can get pregnant
  • It is not affected by other medicines


  • Your periods may become heavier, more painful and longer. However this should improve after the first few months
  • It doesn’t protect against STIs so you will need to use a barrier method of contraception (condoms) too
  • Side effects can include vaginal bleeding and pain. Although uncommon these will stop many women from using the IUD
  • An untreated infection while the IUD is fitted could lead to a pelvic infection

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Who can have an IUD?

Most women can have an IUD fitted, even if you have HIV. A GP or nurse will be able to check your suitability during an appointment at your local Doctor’s surgery or sexual health clinic.

An IUD may not be suitable for you if:

  • You think you might be pregnant
  • You have an untreated pelvic infection or STI
  • You experience problems with your womb or cervix
  • You have unexplained bleeding after sex or between your periods

Do IUDs make you gain weight?

Weight gain is not listed as a side effect with the copper coil, as there is no evidence to support it. The GP or a nurse at your local sexual health clinic will be able to talk through the possible side effects before and after fitting.

Can you get pregnant if you have an IUD?

The IUD is 99% effective at stopping you from getting pregnant. As long as it has been inserted properly by a healthcare professional and it is still in place. It is unlikely that your IUD will come out but it is advised that you check that it is in place often. You can do this by feeling the two thin threads that hang down from your womb into the top of your vagina.