What is it?
A small T-shaped plastic and copper device (there are various types available) that’s inserted into your womb by a specially trained health professional. Depending on the type, an IUD can last from three to 10 years.
How does it work?
By preventing sperm from surviving in the cervix, womb or fallopian tubes. It may also prevent a fertilised egg from implanting in the womb.
How effective is it?
Newer IUDs, which contain more copper than older versions, are over 99% effective. This means that less than one in every 100 women who use one of the new IUDs will become pregnant in a year.
An IUD is effective as soon as it is put in. It can be removed at any time by a specially trained health professional, and normal levels of fertility will return quickly.
Anything else to know about?
It can make your periods heavier, longer or more painful.
There is a very small chance of getting an infection within 20 days after it's fitted, and there's a risk your body might spontaneously expel it. It can also be uncomfortable or painful to insert so discuss any pain relief with your GP or health professional so that you are aware of what you can take or not take to help you.
If you aren't in a monogamous (faithful) relationship you should help protect yourself against sexually transmitted infections by using condoms as well as the IUD.