The intrauterine device


Intrauterine devices, or IUDs, are a long-term method of birth control. This factsheet from fpa explains how it works, the advantages and disadvantages and whether one could be suitable for you.

What is it and how does it work?

The IUD is a small, plastic and copper device that used to be known as the coil. It's inserted into the womb by a doctor or nurse.

One or two soft threads are attached to the end and hang down a little way into the vagina so you can check it's in place. It works for three to ten years, depending on the type used.

The IUD is around 99 per cent effective, depending on the type. This means using this method, less than one woman in 100 may become pregnant in a year.

An IUD can be fitted at any time if it's certain you're not pregnant.

The IUD works by:

* stopping the sperm reaching the egg
* stopping the egg from settling in the womb


Advantages

* It's very effective.
* It doesn't interfere with sex.
* It works as soon as it's fitted.
* It works for three to ten years, depending on the type used.
* You don't have to think about contraception for as long as it works.
* Fertility returns as soon as it's removed.
* If you change your mind, it can easily be removed.


Disadvantages

* Periods may be heavier, longer or more painful.
* It's not suitable for women who are at risk of getting a sexually transmitted infection (STI).
* There's a small risk of infection after fitting.
* The IUD can be pushed out of the womb (expulsion), move or perforate (go through) the lining of the womb or cervix. This is uncommon when fitted by an experienced doctor or nurse. Check the threads every month to make sure it's still in place.
* If you become pregnant using the IUD, there's a small risk of ectopic pregnancy (where the baby develops outside the womb). This is uncommon but dangerous.


Can anyone use an IUD?

The IUD doesn't suit everyone. Reasons not to use it include:

* you think you might be pregnant
* you have an untreated STI, a pelvic infection or are at risk of getting one


You also should not use an IUD if you have now, or have had in the past:

* heavy, painful periods
* unexplained bleeding from the vagina
* problems with your womb or cervix


General comments

You'll need a check-up four to six weeks after it's put in. Do contact your doctor or nurse if you have any problems. You will be taught to feel the threads regularly too.
Where to get it

Contraception is free on the NHS. An IUD can be fitted by a trained GP, nurse or at a family planning clinic.