The Mirena Coil or Intra-Uterine System (IUS) (Fact Sheet)

This leaflet aims to answer your questions about having the intra uterine system (IUS), known as Mirena, inserted. It explains the benefits, risks and alternatives, as well as what you can expect when you come to Newson Health.

What is the IUS?

The IUS is a very small plastic T-shaped device that is inserted into your womb (uterus). It contains a hormone called levonorgestrel (which is a type of progesterone). This hormone is released slowly into your womb.

There are two threads attached to the Mirena coil which pass out through the neck of your womb (cervix) and lie in your vagina. These allow you to check the coil is still there. They also mean it can be removed easily. They do not hang outside the body and your partner does not usually feel them during sexual intercourse.

What is the Mirena coil used for and what are the benefits?

The Mirena coil has a number of uses, including the following:

  • It can be used to protect the lining of your womb as part of hormone replacement therapy (HRT) and can be in place for up to five years.
  • It is widely used as a very reliable contraceptive.
  • It is used as a treatment for heavy and painful periods and can reduce period bleeding by up to 90%. It can be left in place for five years, or longer if you are over the age of 45 when it is inserted and using it just as contracpetion.

What are the risks?

There are very few risks associated with insertion of the Mirena coil:

  • In a small number of women there can be difficulties with the insertion of the Mirena coil. On the rare occasion it is not be possible to fit within our clinic then we will discuss alternative options with you.
  • Very rarely, during insertion, the Mirena coil can make a tiny hole in your womb called a perforation (in about one in every 800 -1,000 insertions) and an operation may then be needed to remove the coil.
  • Occasionally the Mirena coil may fall out of your womb (expulsion). This happens in approximately one in twenty women.

Are there any side effects?

The Mirena coil can cause some irregular bleeding. This is usually not heavy, but is can lead to spotting or having a brown discharge that may continue for up to six months. After this time, it usually settles down and then you usually do not have any bleeding.

Side effects are more common within the first few months of the Mirena coil being inserted and then usually settle after this time. These may include breast tenderness, headaches, acne and symptoms similar to pre-menstrual syndrome (PMS).

Are there any alternatives?

There are types of coils which do not contain any hormones. These can work well for contraception but cannot be used to protect the lining of your womb as part of HRT and also they do not lead to periods reducing or stopping.

There are tablet forms of progesterone that can be used as part of HRT but some women experience side effects with these whereas side effects are far less common with having a Mirena coil.

How can I prepare for having an Mirena coil fitted?

The Mirena can be easily fitted in our clinic. You do not need any special preparation beforehand, although we do recommend that you take your usual painkiller (for example paracetamol) around one hour before your appointment time.

We need to ensure that there is no risk of pregnancy before the Mirena coil is fitted. You will therefore need to ensure that you use adequate contraception or do not have sexual intercourse between your last period and having the Mirena coil fitted.

Asking for your consent

We want to involve you in decisions about your care and treatment. If you decide to go ahead, you will be asked to sign a consent form. This states that you agree to have the Mirena coil inserted and you understand what it involves.

If you would like more information about our consent process, please speak any members of our staff.

Will I feel any pain?

Most women having a Mirena coil inserted do not have any pain. You may feel “period” like discomfort during and after the fitting.

What do I need to do after I go home?

When you leave the clinic you can return to your normal activity. We would suggest that you do not use tampons for the next four weeks. If you are using the Mirena coil for contraception then it will be effective seven days after insertion, so additional contraception (such as condoms) will be needed if you have sexual intercourse in the first week. You may experience some bleeding, which is normal. If you have period pains, you can take your usual painkillers, such as paracetamol or ibuprofen.

Will I have a follow-up appointment?

Most women do not need a follow up appointment. However, if you would like a review appointment to have your Mirena coil checked then you can book this at our clinic.

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