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INTRAUTERINE

DEVICE (IUD)

Other names: non-hormonal coil; copper coil

WHAT IS THE IUD?

The IUD, also called the copper coil, is a small copper and plastic T-shaped device that is placed in your uterus (womb) and releases copper to prevent pregnancy.

It is a highly effective contraceptive and lasts up to 5-10 years depending on the type you choose.

iud

OVERVIEW

EFFICACY

EFFICACY

99%+

FREQUENCY

FREQUENCY

EVERY 5–10 YEARS

EFFECT-ON-FERTILITY

EFFECT ON FERTILITY

UPON DISCONTINUATION OF USE, FERTILITY SHOULD RETURN TO NORMAL

BLOOD-CLOT-RISK

BLOOD CLOT RISK

NOT KNOWN TO INCREASE RISK

HOW DOES AN IUD WORK?

Inhibiting sperm

Copper in the IUD immobilises sperm which makes it more difficult for sperm to reach and fertilise the egg.

HOW EFFECTIVE IS THE IUD?

At 99%, it’s one of the most effective contraceptive methods. An IUD is over 99% effective preventing pregnancy with both perfect use and typical use, meaning that less than 1 in 100 women will get pregnant every year if they have an IUS.

PERFECT USE*

99
%
+

Effective

Approximately

1 out of every 100 women
in a year will experience an unintended pregnancy.

 

* Perfect use of a contraceptive method is when it is used correctly all the time.

TYPICAL USE*

99
%
+

Effective

Approximately

1 out of every 100 women
in a year will experience an unintended pregnancy.

 

* Typical use is what generally happens in real life. It takes into account human error e.g. forgetting to take your pill. For the IUD, typical use is the same as perfect use.

Among 100 women who use no birth control and regularly have sex, it is expected that about 85 will become pregnant in a year.

WHAT IS AN IUD MADE OF?

There are three parts to the IUD:

iud

This is an illustrative example of a T shaped IUD. Different IUDs are available with a range of sizes to accommodate different uterus sizes.

    Is composed of plastic. The arms of the T-shaped frame are folded away into the insertion tube whilst the IUD is being fitted. Once in the womb, the arms are unfolded.

    Copper wire is wound around the vertical arm and sometimes the horizontal arm as well, depending on the type.

    Two soft threads are attached to the base of the t-frame. These threads hang through the cervix into the top of the vagina. The threads are used to remove the IUD, if needed. It is not common for your partner to feel the threads during sex but if they can it shouldn’t cause any pain.

    No. The IUD is hormone free. Because it Is hormone free it does not stop ovulation or interfere with your normal hormonal cycle.

    The IUD is not suitable for everyone. To find out whether the IUD is right for you, talk to a GP, nurse or pharmacist.

    The IUD may not be suitable if you:

    • Are or think you might be pregnant.
    • Have an untreated sexually transmitted infection (STI) or a pelvic infection.
    • Have had an infection or inflammation of your womb following delivery or abortion, during the last 3 months.
    • Have problems with your womb or cervix e.g. fibroids.
    • Have unexplained bleeding between periods or after sex.
    • Suffer from undiagnosed abnormal uterine bleeding.
    • Have Wilson's disease (a disturbance of the body’s copper balance).
    • Have disturbances in blood clotting.
    • Have conditions associated with increased susceptibility to infections.
    • Have untreated cervical dysplasia.
    • Have cancer of the cervix or womb.
    • People who have had an ectopic pregnancy or who have an artificial heart valve must consult their GP or clinician before having an IUD fitted.

    An IUD may also not be the method of first choice if you are young or have not given birth.

PP-UN-WHC-GB-0289 July 2025