IUS Hormonal Coil

The intrauterine system (IUS) is a small plastic device that’s inserted into the womb to act as a contraceptive. It’s highly effective at preventing pregnancy when used properly. Keep reading to find out more about what the IUS is, how it works and who it’s suitable for, as well as possible side effects and risks.


How the IUS works

Also called the hormonal coil, the IUS is a small plastic device that is inserted into your womb by a nurse or doctor. It releases a hormone called progestogen (the synthetic version of progesterone) to prevent you from getting pregnant.

Progestogen thickens the cervical mucus, which makes it harder for sperm to travel through the cervix to reach an egg. It also thins the womb lining, meaning there is less chance of an egg implanting. In some people, it also prevents ovulation.

The device can last for three to five years, depending on the types of IUS you use. If you’re 45 or older when you have the device fitted, it can stay in place until you reach the menopause or don’t need to use contraception anymore.

The IUS is similar to the intrauterine device (IUD), but the IUD releases copper rather than progestogen.


Having an IUS fitted

You can have this device fitted at any point in your menstrual cycle, providing you are not pregnant. If you have it fitted within the first 7 days of your cycle, you’ll be protected against pregnancy immediately. If your IUS is fitted at another point in your cycle, you should use extra contraception such as condoms for 7 days.

The appointment to have the device fitted takes around 15 to 20 minutes in total, and the actual procedure usually lasts 5 minutes or less. Before the nurse or doctor fits the IUS, they will check inside your vagina so they know the size and position of your womb. Your vagina will then be held open, as it is during a smear test, and the IUS will be inserted into your womb through your cervix. Once in place, there will be two threads that hang down through the cervix into the top of your vagina.

Some people find this procedure to be uncomfortable or painful, but you can choose to have a local anaesthetic to reduce pain. If you experience pain while having the device fitted, let the doctor or nurse know. They can stop at any point.

You might find you experience period-like cramps following the procedure, but you may be able to take painkillers to ease this. You may be advised by a doctor to get your IUS checked after 3 to 6 weeks, just to make sure everything is as it should be. Don’t hesitate to let your doctor know if you experience any problems following this check, or if you decide you want to have the device removed.


How can you tell if an IUS is still in place?

You can tell your IUS is still in position by checking the two threads that hang down from it. The doctor or nurse who fits the device will teach you how to feel for the threads.

You should check that it’s still in position a few times during the first month after you get this contraceptive. Following this, check on a regular basis following each period. Although it’s highly unlikely that your IUS will come out, if you can’t feel the threads, you might not be protected against pregnancy, so you’ll need to see your doctor or nurse as soon as possible and use extra contraception in the meantime.

If you think you may have had sex while the IUS wasn’t in position, you might need emergency contraception.


Having an IUS removed

You can decide to have your IUS removed whenever you want. Simply book an appointment with a doctor or nurse and they will do this for you.

Bear in mind that it’s possible to get pregnant immediately after this device has been removed. This means that if you don’t want to become pregnant, you should start using additional contraception 7 days before your IUS is taken out.


Who can use an IUS?

The IUS is suitable for most people with a womb. You can ask your doctor or a nurse if this contraceptive is right for you.

It may not be advised if you have:

  • Unexplained bleeding after sex or between your periods
  • Problems with your cervix or womb
  • Breast cancer, or have recovered from breast cancer in the last 5 years
  • Cancer of the cervix or womb
  • Liver disease
  • Arterial disease, or a history of strokes or heart disease
  • An untreated pelvic infection or sexually transmitted infection (STI)


Using an IUS after an abortion or miscarriage

You can have an IUS fitted by an experienced nurse or doctor straight after a miscarriage or abortion, and you will be protected against pregnancy straight away.


Using an IUS after giving birth

Whether you’ve given birth vaginally or by caesarean, you can usually have an IUS fitted from 4 weeks post-birth. You’ll need to use an alternative type of contraception in the meantime. In some cases, this device can be fitted within 48 hours of birth. Your doctor will be able to advise you on this.

The IUS is safe to use while breastfeeding, and it won’t impact your supply of milk.


How effective is the IUS?

When used correctly, the IUS is more than 99% effective. This means that for every 100 women who use it, less than one will become pregnant over the course of a year. 


Advantages of using an IUS

There are many benefits associated with using this type of contraception. For example:

  • It’s long-lasting (3 or 5 years, depending on the brand).
  • It’s among the most effective types of contraception available.
  • It’s not impacted by you using other medicines.
  • It can make periods less painful, shorter and lighter. They might stop completely after you’ve been using the IUS for a year.
  • It might be a good alternative if you can’t take contraceptives containing oestrogen, such as the combined pill.
  • There’s no evidence that this device increases the risk of womb, ovarian or cervical cancer.
  • It’s possible to get pregnant immediately once you’ve removed the IUS.
  • It’s safe to use if you’re breastfeeding.


Disadvantages of using an IUS

It’s also important to be aware of the potential disadvantages associated with using this contraceptive. For example:

  • Possible side effects can include headaches, breast tenderness and acne (although these effects usually settle over time).
  • Some people find it causes mood changes.
  • An uncommon side effect is the development of small cysts on the ovaries. These usually disappear by themselves without the need for treatment.
  • Because it is not a barrier method of contraception, it doesn’t protect against STIs. This means you may need to use condoms as an additional contraceptive.
  • If you have an infection that goes untreated while using an IUS, it may cause a pelvic infection.


Risks of using an IUS

There are some risks to be aware of before you have an IUS fitted. For example, there is a small chance that you will experience a pelvic infection in the initial weeks after the device is fitted. Make sure you see your doctor if you’re using this method of contraception and you have a high temperature, tenderness or pain in your lower abdomen, or smelly or abnormal discharge.

There is also a small risk that your body will reject the IUS and expel it from your womb, or it might become displaced.

In very rare cases, an IUS can make a hole in the womb when it is fitted. You should see your doctor if you notice changes in bleeding, pain in your lower abdomen or can’t feel your IUS threads.

One more small risk to be aware of is that if this contraceptive fails and you get pregnant, your chance of having an ectopic pregnancy is higher.


Where to get the IUS

You can get the IUS from GP surgeries, contraception or sexual health clinics and certain young people’s services.