Patient information from BMJ

Contraception: intrauterine devices (IUDs)

Last published:Jan 28, 2020

IUDs are small devices that can be placed in your uterus (womb) to stop you becoming pregnant. You need to have one fitted by a doctor or nurse.

You can use our information to talk to your doctor about whether an IUD is the right type of contraception for you.

The right contraception for you

There are many types of contraception to choose from. But they are not all suitable for everyone.

For example, women with heart conditions might not be able to take certain types of contraceptive pill. And people allergic to latex won't be able to use latex condoms, but can use non-latex condoms instead.

The type of contraception that suits you best will depend on several things including:

• your medical history, including things like allergies and any health conditions that you have

• your lifestyle

• whether you need to think about preventing sexually transmitted infections (STIs), including HIV. For example, this applies to you if you have multiple partners, or if you change partners, and

• your own preferences: for example, you might not want to use some types of contraception because you're concerned about side effects. Or maybe you don't want to use condoms because you want something that you don't want to have to think about 'in the moment'.

What are intrauterine devices?

An IUD is a small device that is placed into your uterus (womb). Having one fitted by a doctor or nurse takes about five minutes.

But not all doctors and nurses are trained to fit them. So you might have to go to a special family planning clinic to have one fitted. For example, in the UK these are called Sexual and Reproductive Health Clinics.

There are two types of IUD, which work in slightly different ways to stop you becoming pregnant. They are:

• the copper IUD (sometimes called the 'copper coil') and

• the progestogen IUD.

IUDs are very effective in preventing pregnancy. Other advantages of IUDs include that:

• they are easily reversible. So if you decide you want to try to become pregnant, you can have the IUD removed and start trying straight away

• they are suitable for women who can't or don't want to use contraception methods that contain hormones, such as some contraceptive pills and other devices

• the progestogen IUD can help with heavy or painful periods, and

• once your IUD is in place, you don't need to do anything else.

Possible disadvantages of IUDs include:

• a small chance of getting an infection when the IUD is fitted

• discomfort when the IUD is fitted, and

• problems with your periods, especially with the copper IUD, and especially for the first few months after the IUD is fitted, such as heavier or more painful periods.

There's also a chance that your body might push the IUD out. This is called 'expulsion'. This happens in about 5 in every 100 women. It's more likely to happen:

• in the first year after having it fitted

• if you have never had children

• if you have an IUD fitted soon after giving birth, and

• if you have an IUD fitted soon after having an abortion.

The doctor or nurse who fits your IUD can tell you how to check if it's still in place.

IUDs don't protect against HIV or other STIs.

Copper IUDs

The copper IUD works by slowly releasing small amounts of copper into the womb. This works to prevent pregnancy in several ways. The copper can:

• kill sperm, and

• stop a fertilised egg from implanting in the womb.

A copper IUD can stay in place for between five and 10 years. Your doctor or nurse will tell you how long yours should last.

Copper IUDs can sometimes cause heavier, more painful periods, especially for the first few months.

The copper IUD can also be used as a method of emergency contraception for several days after having unprotected sex.

For more information on emergency contraception, see our leaflet: Contraception: emergency contraception.

Progestogen IUDs

The second type of IUD is the progestogen IUD. It's a similar device to the copper version. But instead of releasing copper into the womb it releases hormones called progestogens.

These hormones prevent pregnancy in several ways, including:

• affecting the cervical mucus so that sperm can't travel along the cervix, and

• thinning the lining of the womb.

A progestogen IUD can stay in place for between three and six years. Your doctor will tell you how long yours will last.

This type of IUD can cause problems in some women, including:

• skin changes

• mood changes

• bloating, and

• breast tenderness.

These symptoms are usually mild and tend to settle down over time.

But the changes in hormones can also help some women, by easing the symptoms of heavy menstrual bleeding and endometriosis.

For more information on some other types of contraception that use hormones, see our leaflet: Contraception: hormonal patches, rings, implants, and injections.

Why contraception matters

The number of unplanned pregnancies tells us how important it is for sexually active people to think about contraception. For example:

• in the UK about 30 in 100 pregnancies are unplanned, and

• in the US about 50 in 100 pregnancies are unplanned.

This is not always bad news, of course: just because a pregnancy is unplanned doesn't mean it's not wanted.

IUDs are a highly effective method of contraception. But they don't suit everyone.

But whatever method you choose, planning and taking responsibility for contraception is vital if:

• you are a sexually active and want to play a responsible part in preventing an unwanted pregnancy

• you think that you might be at risk of HIV or other STIs (for example, if you have multiple sexual partners) and you want to use a method of contraception that protects against infection.

Very few methods of contraception are totally effective. But planning gives you the best chance of being in control of when and if you become pregnant.

Your doctor or practice nurse will be very happy to discuss contraception and family planning methods that best suit you.