Mirena Coil

An intrauterine system (IUS)

The intrauterine system (IUS) is one method of contraception (family planning). It is sometimes referred to as the hormonal coil.

A specially trained female IPSA doctor inserts the small, T-shaped, plastic IUS device into your uterus (womb).

The hormone progestogen is released into the womb by the IUS and it acts by thickening the mucus in your cervix, thus making it difficult for the sperm to move through your cervix and reach the egg.

The IUS is effective for five years. This means that you will no longer have to think about contraception each time you have sex or on a daily basis.


What is the Mirena coil?

In the UK, the IUS that is used has the brand name ‘Mirena’.

An IUS can be used whether or not you have had any children.


IUS facts

  • The IUS is over 99% effective.
  • A specially trained IPSA practitioner can take the coil out at any time. Coil removal leads to your fertility returning to normal fairly quickly.
  • It may help women with heavy or painful periods, as the IUS can make your periods shorter, lighter or it can make them stop altogether.
  • The IUS is suitable for women who cannot use forms of combined contraception (for example, the combined pill), such as women who suffer from migraines.
  • Once the IUS has been inserted, you will no longer have to think about contraception each time you have sex or on a daily basis.
  • The IUS may cause side effects such as skin problems, breast tenderness or mood swings.
  • Post-insertion, there is a small risk of developing an infection.
  • There can be some discomfort when the IUS is being fitted. Painkillers are useful when the IUS is being inserted.
  • As long as you are not pregnant, the IUS can be fitted at any point during your menstrual cycle. To protect yourself immediately from an unwanted pregnancy, the IUS should be fitted within seven days of the start of your period. Using condoms for seven days if the IUS has been fitted at any other time during your cycle is recommended.
  • An IUS does not protect you against any STIs (sexually transmitted infections). Combining condom use and the IUS will help in protecting you against STIs.


Where can I get the coil?

Prior to fitting the coil at your IPSA clinic, the position and size of your womb needs to be determined through an internal examination to ensure that the coil can be put in the correct position. At the IPSA clinic, your IPSA practitioner is skilled at fitting coils and she will ensure that the atmosphere is private, safe and conducive. At this point, you may be tested for any infections (e.g. sexually transmitted infections), as it is best to treat any infections that you may have before the coil is fitted. You may sometimes be prescribed antibiotics by your IPSA clinician at the same time as your coil is fitted.

The coil takes approximately 15–20 minutes to insert. As with a cervical smear test, your vagina is held open for the process, and the coil is then inserted into your womb through the cervix.

The fitting process can sometimes be a little uncomfortable and you may experience some cramps following the fitting.

If you experience any of the following symptoms after having your IUS fitted, then see your IPSA doctor or return to your IPSA clinic where you had your IUS fitted as soon as possible, as these symptoms can mean that you have an infection:

  • Pain in your lower abdomen
  • A high temperature
  • A smelly discharge


How to tell if an IUS is still in place

Two thin threads hang down slightly from your womb into the top area of your vagina from the IUS. To check that your IUS is still in the correct place, your IPSA clinician who has fitted your IUS will teach you how to feel for the threads.


Advantages and disadvantages of the IUS

The IUS is effective as a method of contraception; however, there are a few things to consider before having your IUS fitted.

Advantages of the IUS

  • It is effective for five years
  • The IUS is one of the most effective types of contraception currently available in the UK
  • The IUS does not interrupt sex
  • After the first year using an IUS, you periods may stop entirely. If you have had painful or heavy periods, then using an IUS may make your periods shorter or much lighter, and sometimes your periods also become less painful
  • If you are breastfeeding, then you can use an IUS safely
  • Medicines do not affect the IUS
  • If you are unable to take the hormone oestrogen (which is in the combined contraceptive pill), then the IUS may be a viable option for you
  • When the IUS is removed, your fertility level quickly returns to normal

Disadvantages of the IUS

  • Your periods can stop entirely, they may become irregular and they may also become lighter
  • Although irregular spotting and bleeding are common for the first six months following fitting, this usually lessens with time
  • There are some side effects for some women, such as acne, breast tenderness and headaches
  • An IUS does not protect against STIs (sexually transmitted infections). Combining condom use and the IUS will help in protecting you against STIs.


Risks with the IUS

Complications are rare with an IUS and they usually arise during the first six months after fitting:

  • Womb damage: In every 1000 women having an IUS fitted,  less than one will experience an IUS perforating (making a hole in) the womb/neck of the womb (cervix) when it is inserted. The perforation risk is extremely low.
  • Pelvic infections: For the first 20 days following the IUS being inserted, there is a slight risk of pelvic infections. This risk is extremely small, with less than one in 100 women who have a low STI risk getting an infection.
  • Rejection: Very rarely, the IUS can be expelled (rejected) by the womb or the IUS can move (this is termed ‘displacement’). This is uncommon and it is more likely to occur shortly after the IUS has been fitted.
  • Ectopic pregnancy: The IUS should be removed as soon as possible if you happen to fall pregnant through the IUS failing and if you wish to continue with the pregnancy.


If you are thinking about having the Mirena coil as your chosen form of contraception, then book an IPSA Mirena coil consultation today.


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