IUD (intrauterine device, coil)

An IUD is a small T-shaped plastic and copper device that’s inserted into your womb (uterus) by a specially trained doctor or nurse.

The IUD works by stopping the sperm and egg from surviving in the womb or fallopian tubes. It may also prevent a fertilised egg from implanting in the womb.

The IUD is a long-acting reversible contraceptive (LARC) method. This means that once it's in place, you don't have to think about it each day or each time you have sex. There are several types and sizes of IUD.

You can use an IUD whether or not you've had children.

At a glance: facts about the IUD

There are different types of IUD, some with more copper than others. IUDs with more copper are more than 99% effective. This means that fewer than 1 in 100 women who use an IUD will get pregnant in one year. IUDs with less copper will be less effective.

An IUD works as soon as it's put in, and lasts for 5 to 10 years, depending on the type.

It can be put in at any time during your menstrual cycle, as long as you're not pregnant.

It can be removed at any time by a doctor or nurse and you'll quickly return to normal levels of fertility.

Changes to your periods are common in the first 3 to 6 months after an IUD is put in. For example, your periods may be heavier, longer or more painful. But they're likely to settle down after this. You might get spotting or bleeding between periods.

There's a very small chance of infection within 20 days of the IUD being fitted.

There's a risk that your body may expel the IUD.

If you get pregnant, there's an increased risk of ectopic pregnancy. But because you're unlikely to get pregnant, the overall risk of ectopic pregnancy is lower than in women who don't use contraception.

Having the IUD put in can be uncomfortable. Ask the doctor or nurse about pain relief.

An IUD may not be suitable for you if you've had previous pelvic infections.

The IUD does not protect against sexually transmitted infections (STIs). Use condoms as well as the IUD, to protect yourself against STIs.

How an IUD works

The IUD is like the IUS (intrauterine system) but works in a different way. Instead of releasing the hormone progestogen like the IUS, the IUD releases copper. Copper changes the make-up of the fluids in the womb and fallopian tubes, stopping sperm surviving there. IUDs may also stop fertilised eggs from implanting in the womb.

There are types and sizes of IUD to suit different women. IUDs need to be fitted by a doctor or nurse at your GP practice or sexual health clinic.

An IUD can stay in the womb for 5 to 10 years, depending on the type. If you're 40 or over when you have an IUD fitted, it can be left in until you reach the menopause or until you no longer need contraception.

Having an IUD fitted

An IUD can be fitted at any time during your menstrual cycle, as long as you're not pregnant. You'll be protected against pregnancy straight away.

Before you have an IUD fitted, you'll have an internal examination to find out the size and position of your womb. This is to make sure that the IUD can be put in the correct place.

You may also be tested for infections, such as STIs. It's best to do this before an IUD is fitted so that you can have treatment (if you need it) before the IUD is put in. Sometimes, you may be given antibiotics at the same time as the IUD is fitted.

The fitting process can be uncomfortable and sometimes painful. You may get cramps afterwards. You can ask for a local anaesthetic or painkillers before having the IUD fitted. An anaesthetic injection itself can be painful, so many women have the procedure without.

You may get pain and bleeding for a few days after having an IUD fitted. Discuss this with your doctor or nurse beforehand.

The IUD needs to be checked by a doctor after 3 to 6 weeks. Speak to your doctor or nurse if you have any problems before or after this first check or if you want the IUD removed.

See your GP or go back to the clinic where your IUD was fitted as soon as you can if you have:

  • pain in your lower abdomen
  • a high temperature
  • a smelly discharge

These signs may mean you have an infection. You should also speak to your GP if you think you're pregnant.

It's important that the IUD threads are checked about 6 weeks after it's put in. Most people do this themselves, but you can ask a doctor or nurse to check it for you if you don't want to do it.

How to tell whether an IUD is still in place

An IUD has 2 thin threads that hang down a little way from your womb into the top of your vagina. The doctor or nurse who fits your IUD will teach you how to feel for these threads and check that it's still in place.

Check your IUD is in place a few times in the first month, and then after each period or at regular intervals.

It's very unlikely that your IUD will come out. But if you can't feel the threads, or if you think the IUD has moved, you may not be fully protected against getting pregnant. See your doctor or nurse straight away and use an extra method of contraception, such as condoms, until your IUD has been checked. If you've had sex recently, you may need to use emergency contraception.

Your partner shouldn't be able to feel your IUD during sex. If they can feel the threads, get your doctor or nurse to check that your IUD is in place. They may be able to cut the threads to a shorter length. If you feel any pain during sex, go for a check-up.

Removing an IUD

An IUD can be removed at any time by a doctor or nurse.

If you're not going to have another IUD put in and you don't want to get pregnant, use another method of contraception (such as condoms) for 7 days before you have the IUD removed. This is to stop sperm getting into your body. Sperm can live for up to 7 days in the body and you could become pregnant once the IUD is removed.

As soon as an IUD is taken out, your normal fertility should return.

Who can use an IUD?

Most women can use an IUD. This includes women who have never been pregnant and those who are HIV positive. Your doctor or nurse will ask about your medical history to check if an IUD is the most suitable form of contraception for you.

You should not use an IUD if you have:

  • an untreated STI or a pelvic infection
  • any unexplained bleeding from your vagina – for example, between periods or after sex, until this has been investigated

You should not be fitted with an IUD if there's a chance that you're already pregnant or if you or your partner are at risk of catching STIs. If you or your partner are unsure, go to your GP or a sexual health clinic to be tested.

Using an IUD after giving birth

An IUD can usually be fitted 4 to 6 weeks after giving birth (vaginal or caesarean). You'll need to use alternative contraception from 3 weeks (21 days) after the birth until the IUD is fitted. In some cases, an IUD can be fitted within 48 hours of giving birth and at the time of a caesarian section. An IUD is safe to use when you're breastfeeding and it won't affect your milk supply.

Using an IUD after a miscarriage or abortion

An IUD can be fitted straight away or within 48 hours after an abortion or miscarriage by a doctor or nurse, as long as you were pregnant for less than 24 weeks. If you were pregnant for more than 24 weeks, you may have to wait a few weeks before having an IUD fitted.

Advantages and disadvantages of an IUD

Although an IUD is an effective method of contraception, there are some things to consider before having one fitted.

Advantages of an IUD

Advantages of an IUD are that:

  • most women can use it, including women who have never been pregnant
  • once it's fitted, it works straight away and lasts for up to 10 years (depending on type) or until it's removed
  • it doesn't interrupt sex
  • it can be used if you're breastfeeding
  • your normal fertility returns as soon as the IUD is taken out
  • it's not affected by other medicines
  • it does not contain hormones

Disadvantages of an IUD

Disadvantages of an IUD are that:

  • your periods may become heavier, longer or more painful, though this may improve after a few months
  • it doesn't protect against STIs, so you may have to use condoms as well – if you get an STI while you have an IUD, it could lead to a pelvic infection if not treated
  • the most common reasons that women stop using an IUD are vaginal bleeding and pain

Risks of an IUD

Complications after having an IUD fitted are rare. Most will appear within the first year after fitting.

Perforation of the womb

In rare cases an IUD can perforate (make a hole in) the womb or cervix when it's put in. This happens in fewer than 1 in 1,000 insertions. If the doctor or nurse fitting your IUD is experienced, the risk is extremely low. If perforation occurs, you may need surgery to remove the IUD.

Perforation can cause pain in the lower abdomen but is usually painless. It doesn't usually cause any other symptoms. The first sign is usually that the threads cannot be felt. Although the usual reason for this is that the threads have curled up into the cervix.

Contact your GP or sexual health if you can’t feel the threads after having an IUD fitted.

Pelvic infections

Pelvic infections may occur in the first 21 days after the IUD has been inserted. The risk of infection from an IUD is extremely small. Fewer than 1 in 100 women who are at low risk of STIs will get an infection. Contact the service who put it in for you if you have:

  • an unusual discharge
  • persistent abdominal pain
  • bleeding

Expulsion or displacement

5 in every 100 IUDs are ejected (expelled) by the womb. This is more likely to happen soon after it has been fitted. But it can happen later, which is why you should check the threads once a month. Your doctor or nurse will teach you how to check the threads.

An IUD can move inside the womb. This is called displacement. This can cause spotting between periods and lower abdominal pains like cramp. If you get this speak to your GP or sexual health clinic. There can be other causes which can be checked.

Ectopic pregnancy

If the IUD fails and you become pregnant, your IUD should be removed as soon as possible if you're continuing with the pregnancy. There's a small increased risk of ectopic pregnancy if a woman becomes pregnant while using an IUD, so an early ultrasound is advisable. You should contact your local early pregnancy unit or GP as soon as possible if you have a positive pregnancy test and an IUD in place. If you have an IUD and severe abdominal pain, a pregnancy test should be done.

Where can you get an IUD?

Most types of contraception are available for free in the UK. Contraception is free to all women and men through the NHS. Places where you can get an IUD include:

Contraception services are free and confidential, including for people under the age of 16.

If you're under 16 and want contraception, the doctor, nurse or pharmacists won't tell your parents or carer, as long as they believe you fully understand the information you're given, and your decisions.

Doctors and nurses work under strict guidelines when dealing with people under 16. They'll encourage you to consider telling your parents, but they won't make you. The only time that a professional might want to tell someone else is if they believe you're at risk of harm, such as abuse. The risk would need to be serious, and they would usually discuss this with you first.

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Source: Scottish Government

Last updated:
05 May 2023

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