IUS (intrauterine system)

An intrauterine system (IUS) is a small T-shaped plastic device.

It’s more than 99% effective. Less than 1 in every 100 people who use an IUS will get pregnant in 5 years.

It’s inserted into your womb (uterus) by a doctor or nurse to prevent pregnancy. It does not protect you against sexually transmitted infections (STIs).

Intrauterine system (IUS)

How an IUS works

An IUS works in a different way from the copper coil (IUD).

It works for 3 to 8 years.

An IUS prevents pregnancy by releasing progestogen which:

  • prevents you from releasing an egg (ovulating)
  • makes it difficult for sperm to get to an egg
  • thins the womb lining, so there’s less chance an egg will attach to it

If you’re 45 or older when an IUS is fitted, it can be left in until you reach menopause or no longer need contraception.

You can use an IUS whether or not you’ve had children.

It’s safe to use any period product (including a tampon or menstrual cup) with an IUS

When it starts to work

You can have an IUS put in at any time during your menstrual cycle, as long as you’re not pregnant.

If it’s put in during the first 7 days of your cycle, you’ll be protected against pregnancy.

If it’s put in on any other day of your menstrual cycle, you should use additional contraception such as condoms for 7 days.

After giving birth

You can have an IUS fitted within 48 hours of giving birth.

If it’s not fitted within 48 hours you can have it fitted 4 weeks after the birth. Until then you should use a different method of contraception, such as condoms.

An IUS is safe to use while you’re breastfeeding.

After a miscarriage or abortion

An IUS can be fitted immediately after a miscarriage or an abortion. You’ll be protected from pregnancy straight away.

Having an IUS fitted

Before your IUS is fitted, a doctor or nurse will check inside your vagina to check the position and size of your womb.

You may also be tested for any infections, such as STIs.

Your appointment should take 15 to 20 minutes, and fitting the IUS should take no longer than 5 minutes.

During the fitting process:

  • your vagina is held open like it is during a smear test
  • the IUS is put in through the cervix into the womb

Having an IUS fitted can be uncomfortable or painful. You may also experience cramps.

You can ask for a local anaesthetic to help. You can also take painkillers before and after having an IUS fitted.

Once your IUS is fitted, you may be advised to get it checked by your doctor or nurse after 3 to 6 weeks to make sure everything is fine.

Speak to your GP practice if you or your partner are at risk of getting an STI, as this can lead to infection in the pelvis.

Speak to your GP practice or go back to the clinic if you have:

  • pain in your lower tummy (abdomen)
  • a high temperature
  • smelly discharge

How to tell it’s still in place

An IUS has 2 thin threads that hang down slightly from your womb into the top of your vagina.

The doctor or nurse that fits your IUS will show you how to feel for these threads and check that the IUS is still in place.

Check your IUS is in place after 4 weeks or after your first period. Then check once a month.

It’s unlikely that your IUS will come out, but if you can’t feel the threads or if you think the IUS has moved, you may not be protected against pregnancy.

Speak to your doctor or nurse and use additional contraception such as condoms until you’ve had your IUS checked.

If you’ve had sex recently, you may need emergency contraception.

Your partner should not be able to feel your IUS during sex. If they can, see your doctor or nurse for a check-up.

Removing an IUS

Your IUS can be removed at any time by a doctor or nurse.

If you’re not having another IUS put in and don’t want to become pregnant, you should use additional contraception such as condoms for 7 days before you have it removed.

You may be able to get pregnant as soon as your IUS has been taken out.

Who can use an IUS?

Most women can use an IUS, however it might not be suitable for some people. Your doctor or nurse will talk about this with you.

You should not use an IUS if you have:

Side effects of an IUS

An IUS may cause side effects such as:

  • irregular bleeding and spotting during the first 6 months after having an IUS fitted – this is not harmful and usually decreases with time
  • headaches
  • acne
  • breast tenderness

Benefits of using an IUS

Some benefits of using an IUS are that:

  • it works for 3 to 8 years
  • it’s one of the most effective forms of contraception available
  • it doesn’t interrupt sex
  • it may be useful if you have heavy or painful periods because your periods usually become much lighter and shorter, and sometimes less painful – they may stop completely after the first year of use
  • it can be used safely if you’re breastfeeding
  • it’s not affected by other medicines
  • it may be a good option if you can’t take the hormone oestrogen, which is used in the combined contraceptive pill
  • your fertility will return to normal when the IUS is removed

Risks of using an IUS

There are some risks of using an IUS, but they are not common. They include:

You should speak to your doctor or nurse about this before starting an IUS.

Where can you get an IUS?

If you’re under 16

Anyone can get contraception for free in Scotland, even if you’re under 16.

Contraception services are confidential so the person won’t tell anyone else about it. You can ask them any questions you may have.

If you’re under 16, they might encourage you to tell your parents, but you do not have to.

The only time a professional might need to tell someone else is if they think you’re at risk of harm, such as abuse. The risk would need to be serious. They’d usually talk about it with you first.

Last updated:
30 December 2022