Hormonal coil (IUS)

Benefits

  • Works for three or five years
  • You don’t have to prepare for or interrupt sex
  • You don’t have to remember to take a pill everyday
  • If you have heavy or painful periods, the IUS can make your periods lighter, shorter, and sometimes less painful – they may stop completely
  • Fertility will return to normal when the IUS is removed
  • The IUS is not affected by other medicines.

The hormonal coil, also known as the IUS (intrauterine system) is a small T-shaped plastic device that sits in your womb and releases the progestogen hormone. It is long-acting and reversible, so you can take it out if you want to get pregnant.

It is the sixth most popular method of contraception in the UK, and is becoming more popular, particularly amongst women over 25.

Read what other people think of the hormonal coil on our contraception forum.

How it works

How to use it

A clinician will insert the small, T-shaped plastic device into your womb (uterus).

Once the IUS is in place, you don't have to think about contraception. It won't interrupt sex and your partner should not be able to feel it. There are two brands of IUS hormonal coil available in the UK - the Mirena coil lasts for five years, and the Jaydess coil for three years.

It can be removed at any time by a trained doctor or nurse, but you must use condoms as well or abstain from sex for 7 days prior to removal.

Why it works

The IUS releases a progestogen hormone which prevents pregnancy by:

  • Thickening the mucus in the neck of the womb, so it is harder for sperm to penetrate the womb and reach an egg
  • Thinning the lining of the womb, so there is less chance of a fertilised egg implanting into the womb
  • In some women, the IUS also stops the ovaries from releasing an egg (ovulation), but most women will continue to ovulate.
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Things to consider

What if?

The IUS doesn’t stay in place:

An IUS has two thin threads that hang down a little way from your womb into the top of your vagina. You will be taught how to feel for the threads and check the IUS is still in place. If you can't feel the threads or if you think the IUS has moved, you may not be fully protected against pregnancy. See your doctor or nurse straight away and use extra contraception, such as condoms, until your IUS has been checked.

It’s highly unlikely that your IUS will come out.

Suitability

Most women can use an IUS, but your clinician will ask about your family and medical history to find out whether it’s right for you.

The IUS is suitable for women who can’t take the hormone oestrogen (which is in the combined pill).

IUS may not be suitable for you if you have or have had certain health conditions.

Side effects & risks

Common Rare
Short term:

Irregular bleeding and spotting in the first six months. This is not harmful and usually decreases with time.

Some women experience headaches, acne and breast tenderness after having the IUS fitted.

Pelvic infections may occur in the first 20 days after the IUS has been inserted. Fewer than 1 in 100 women will get an infection.

Long term:

Minor changes in mood and libido.

Irregular vaginal bleeding and pain.

Small fluid-filled cysts on the ovaries – these usually disappear without treatment.

Questions?

Before you have a coil fitted, you may be tested for any existing infections, such as STIs, so that any infections can be treated beforehand.

The coil can be fitted at any time during your monthly menstrual cycle, as long as you're definitely not pregnant.

Having a coil fitted can be uncomfortable and painful but the pain shouldn't last long and is described as quite similar to period pains. A fitting is likely to be less painful if you have had natural birth (vaginal delivery) as your cervix will have previously been stretched.

Whilst you lie down, with your knees bent, a speculum will be used to hold your vagina open (the same instrument is used when having a smear test done). Local anaesthetic gel is applied to the cervix and this feels cold.

The clinician will then use forceps to hold the cervix steady in order to determine the size and position of your womb with a sterile probe.

The coil comes with its arms folded down packed inside a narrow tube. The clinician will insert the tube into the vagina, through the cervix and into your uterus (womb).

Then they will pull the plastic tube out, leaving the coil in place allowing the arms of the coil to fold open. Before the speculum is removed, the strings of the coil are cut, leaving 1 to 2 cm hanging down at the top of your vagina so that you can feel to make sure it is still in place.

The whole process should take about 5 minutes.

People normally have some cramping pain afterwards so it is recommended you take some pain killers just before your appointment.

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If it is fitted in the first five days of your menstrual cycle you will be immediately protected against pregnancy. If it is fitted at any other time, you will need to use additional contraception for the first 7 days.

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The non-hormonal coil IUD releases copper that creates an environment where sperm do not survive.

The hormonal coil IUS releases a progestogen hormone, which thickens the mucus from the cervix (opening of the womb), making it harder for sperm to move through it and reach an egg. It also causes the womb lining to become thinner and less likely to accept a fertilised egg. In some women, the IUS also stops the ovaries from releasing an egg (ovulation), but most women will continue to ovulate.

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Your partner shouldn't be able to feel your IUS during sex. If he can feel the threads, get your GP or clinician to check your IUS is in place. They may be able to cut the threads a little.

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There is a very small risk of infection. If you have any of the following symptoms within a few days of having an IUS fitted, you should see your GP (or clinician who fitted the IUS) straight away:

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

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Fertility will return to normal when the IUS is removed.

If you decide to have your IUS taken out, but you don’t want to get pregnant, you will need to use condoms for 7 days before you have it removed. This is because sperm can live for up to 7 days inside the body.

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There's no evidence that an IUS will affect your weight.

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The GP or clinician that fits your IUS will teach you how to feel for the threads and check that the IUS is still in place. If you can't feel the threads or if you think the IUS has moved, you may not be fully protected against pregnancy. See your doctor or nurse straight away and use extra contraception, such as condoms, until your IUS has been checked.

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Having a coil fitted can be uncomfortable and painful but the pain shouldn't last long and is described as quite similar to period pains. A fitting is likely to be less painful if you have had natural birth (vaginal delivery) as your cervix will have previously been stretched.

The clinician doing the fitting will use a speculum to hold your vagina open (the same instrument is used when having a smear test done). Local anaesthetic gel is applied to the cervix and this feels cold.

Read more about the coil fitting process.

Occasionally people feel nauseous or faint afterwards. They may need to lie down for 5-10 minutes but are usually fine after a short while. The clinician will always make sure you are recovered and happy to make your way home before letting you leave.

Some people prefer to have no plans after their appointment so that they can be relax at be comfortable at home afterwards.

It is fairly common for women to experience some slight cramping and / or spotting for a couple of days after a fitting. You will be asked to make an appointment after 6 weeks where the clinician will check your coil is in place and to see how you are getting on.

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There's no evidence that having an IUS fitted will increase the risk of cervical cancer, cancer of the uterus or ovarian cancer.

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In fewer than 1 in 1,000 cases, an IUS can make a tiny hole in the womb or neck of the womb (cervix) when put in. The risk of perforation is extremely low. Contact your GP straight away if you feel a lot of pain in the lower abdomen after having an IUS fitted. If there is a suspected perforation, go to A&E to see a specialist. If perforation occurs, you may need surgery to remove the IUS.

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The coil can be pushed out by your uterus or it can move. This is not common. This is more likely to happen soon after it has been put in. This is why your doctor or nurse will teach you how to check your coil threads every month and also arrange to check it for you 6 weeks after your fitting.

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If you get an STI while you have an IUS fitted, it could lead to pelvic infection. STIs and pelvic infections need to be treated as soon as possible. An IUS doesn't protect you against STIs, so you may also have to use condoms when having sex.

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Although this is unlikely, if the IUS fails and you become pregnant, you should have it removed as soon as possible if you are continuing with the pregnancy. You should also have a scan to ensure the pregnancy is not ectopic.

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Yes, you can fit the IUS more than 28 days post-delivery.

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An IUS can be used safely while you are breastfeeding and will not affect your milk supply.

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Most women can use an IUS, but your GP or clinician will ask about your family and medical history to find out whether it’s right for you.

The IUS is suitable for women who can’t take the hormone oestrogen (which is in the combined contraceptive pill).

IUS may not be suitable for you if you have or have had certain health conditions.

  • Breast cancer or have had it in the past five years
  • Cervical cancer
  • Liver disease
  • Heart disease
  • Problems with your womb or cervix or unexplained vaginal bleeding between periods or after sex
  • An untreated STI or pelvic infection.

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If you're 45 or older when you have the IUS fitted, it can be left until you reach menopause or you no longer need contraception.The IUS can also be used for HRT.

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Yes, whilst using the IUS you can use tampons, pads or a mooncup.

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A coil can be removed at any time by a trained doctor or nurse.

If you're not going to have another coil put in and you don't want to get pregnant, use another method (such as condoms) for seven days before, as sperm can live for up to seven days inside the body.

Removal of a coil is a very quick procedure (about 30 seconds). It may be a little uncomfortable but is much less uncomfortable than the fitting procedure.

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Where can I get it?

The IUS is free on the NHS. It can be fitted by most sexual health clinics and some GPs. Talk to your clinician about whether it’s right for you. Your clinician will be able to tell you where you can get it fitted nearby, if they can’t do it themselves.

The IUS can be fitted at any time during your monthly menstrual cycle, as long as you're definitely not pregnant.