Copper Intrauterine Devices (Cu-IUD)

A copper intrauterine contraceptive device (Cu-IUD) is a small, T-shaped, plastic device with copper on the stem (and sometimes the arms too)
Copper is toxic to sperm and thus prevents fertilization and pregnancy from occurring
It sits inside the womb and is also known as the ‘copper coil’
Over 99% effective
Lasts 5–10 years depending on the type
Fitted and removed by a specialist doctor or nurse
Does not protect against sexually transmitted infections (STIs)

The Cu-IUD contains copper which destroys sperm and eggs, preventing fertilisation
It also prevents pregnancy from developing in the lining of the womb (implantation)
It is generally safe and does not normally cause any harm or damage to the womb
There are several types of IUD available
It is >99% effective, meaning less than 1 person per 100 users will fall pregnant within a year while using a copper IUD

Once fitted, the Cu-IUD works straight away:

It can be fitted at any time during your cycle as long as you are not already pregnant from unprotected sex earlier in your cycle
It is the best method of emergency contraception and can be used up to 5 days after unprotected sex or 5 days after the earliest predicted time of ovulation
It can be fitted 4 weeks after childbirth (or within the first 48 hours of delivery). You cannot get pregnant within 21 days of childbirth, but you must use additional contraception after this time until the IUD is fitted
It can be inserted immediately following complete miscarriage or abortion and works straight away

There are no hormonal side effects from the Cu-IUD and your periods should remain the same
Irregular bleeding can occur, especially in the first few months. This usually settles with time
Occasionally periods can become heavier and more painful
Future fertility is not affected by the Cu-IUD; you can become pregnant as soon as it is removed
There is a small risk of infection and/or damage to the womb when it is fitted (called a perforation)
There is also a small risk the Cu-IUD falls out (called an expulsion). This is usually within the first 4 months after insertion.
Although the Cu-IUD is very effective, if a pregnancy did occur, there is increased risk this would be an ectopic pregnancy. This is when a pregnancy develops outside the womb, such as in the fallopian tube

A specialist nurse or doctor will fit the Cu-IUD for you
You will be examined to assess the size and position of your womb
A speculum is used to open the vagina and visualise the cervix (neck of the womb)
The Cu-IUD is gently inserted through the cervix and into the womb
A local anaesthetic spray or injection can be used
The procedure is very quick and will only take a few minutes
You may experience some cramping and bleeding afterwards, but this will settle down in a few days

The Cu-IUD contains two soft threads attached to the bottom of the device
These threads pass through the cervix and sit at the top of the vagina
Your partner will not be able to feel the threads during sexual intercourse
You can check the Cu-IUD is still in place by inserting a finger into the top of the vagina and feeling for the threads
It is important to regularly check your threads so that you know the Cu-IUD is still in place
If you can no longer feel the threads, speak to your doctor and use another method of contraception until it can be identified. This is because the Cu-IUD might have fallen out

The Cu-IUD provides contraception for 5–10 years depending on the type of device
You will be provided with written information advising you when your Cu-IUD needs to be changed
A specialist nurse or doctor can remove the Cu-IUD at any time
A speculum is used to find the threads of the Cu-IUD. It is removed by gently pulling on the threads

You can get a Cu-IUD fitted free of charge at:

The Cu-IUD is safe to use in the majority of users; however, there are some circumstances where it may not be appropriate.

Always discuss with the doctor or nurse if:

There is a chance you are already pregnant
You have symptoms of infection or have been recently diagnosed with an STI such as chlamydia or gonorrhoea
Your periods are usually very painful or heavy
Your womb is an abnormal shape
You have a history of cervical or womb cancer
You have bleeding in between your periods or after sex which has not been investigated

Written by Dr David Rook and Dr Paula Briggs
Reviewed and edited by Dr David Rook
Last updated: July 2025 by Dr David Rook

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