The Intra-Uterine System (IUS) 'Mirena Coil' Patient Information

This section aims to answer your questions about the intra uterine system (IUS), known as Mirena. It explains the benefits, risks and alternatives, as well as what to expect when you come to the surgery.

What is the IUS?

The Mirena IUS is a small plastic T-shaped device containing progestogen hormone (levonorgestrel).

It is fitted into the womb where the hormone is released slowly over 5 years. It has two fine threads that come through the cervix (neck of the womb) opening and rest at the top of the vagina, in order to be checked and removed when necessary. There are alternate IUS devices available in the practice, which you may wish to discuss.

What is the IUS used for and what are the benefits?

Long term contraception

The Mirena is widely used as a long term reversible contraceptive and can be left in place for up to five years (or longer if you are over the age of 45). It is one of the best forms of contraception, with only two in 1,000 women getting pregnant (0.2%)

However, should you wish to get pregnant, fertility returns to Normal when the Mirena is removed.

Heavy, painful periods

It is used as a treatment for heavy periods and can reduce period bleeding by up to 90%. In addition, up to 50% of women will have no periods after one year of use. The Mirena coil has been successfully used to reduce period pains and is a known treatment for conditions such as endometriosis.

HRT

It can be used as part of HRT to provide womb lining protection. Most benefits of HRT come from oestrogen, however, if given alone, it causes thickening of the lining of the womb leading to irregular bleeding and other problem.

Many women are unaware that they may still need contraception even if they are taking HRT (this should be discussed with your GP). A further advantage is that the Mirena coil is the only 'progesterone part' of HRT that can double up as contraception.

Avoiding surgery

It is much safer to insert a Mirena than to have surgery for heavy periods, or a sterilisation for contraception.

Medication interaction

The Mirena coil is not affected by other medicines and is safe to use whilst breastfeeding.

What are the risks?

Difficulty with insertion

Occasionally, there can be difficulties for example if your cervix is tightly closed. This is more common in those who have had surgery to the cervix, or not had children vaginally. Your doctor may be able use equipment to help open the cervix. If this is not possible you may need to be referred to the hospital to have it fitted.

Perforation

Rarely, the Mirena coil might go through the wall of the womb. This risk may be higher if breastfeeding. One sign maybe pain, but often there are no symptoms and the womb will heal by itself.

Expulsion

Rarely, the Mirena may be pushed out of the womb or displaced. Your nurse will teach you how to check your threads are in the correct place, which you should do every few months.

Infection

There's a small chance of getting a pelvic infection during the first few weeks after an IUS is put in.

Ectopic pregnancy

The Mirena is very effective and it is unlikely you'll get pregnant. If you do, there's a small increased risk of it developing outside the womb.

Are there side effects?

Side effects are more common within the first few months and generally settle after continued use.

Hormonal

These may include breast tenderness, headaches, acne and symptoms similar to PMS.

Bleeding problems

Some women may experience changes to their bleeding patterns. This usually settles by 3-6 months. We encourage you persevere and speak to your GP if you find this difficult.

Ovarian cysts

Occasionally, women may develop functional or simple ovarian cysts (small fluid filled sacs on the ovaries), which are not dangerous. They usually cause no symptoms and go away on their own.

Am I suitable for the Mirena Coil?

There are some women for whom the IUS is not suitable. This will be assessed at the time of counselling. In particular, please inform us if you have any of the following:

• allergy to progesterone/levonorgestrel
• suspected pregnancy
• unexplained vaginal bleeding
• pelvic inflammatory disease (current or within the last three months)
• changes to the shape of the womb.

How can I prepare for having an IUS fitted?

Timing of fitting

An IUS can be put in at any time in your menstrual cycle. If fitted in the first seven days of your menstrual cycle, you do not require any further contraception. If fitted at any other time, you will need  additional contraception for the first seven days.

Ensuring you are not pregnant

Prior to having your IUS fitted, you will need to ensure you use adequate, reliable contraception or do not have sexual intercourse from your last period. Please inform us if there is a possibility you are pregnant.

Previous infections

Your nurse will check if you are at risk of infections including previous sexually transmitted infections or a new partner within the last 12 months. We may recommend you have a sexual health screen/ vaginal swabs prior to/at the time of your coil fitting.

Heart conditions

Tell your nurse/doctor if you have an abnormal heart valve, as you might need antibiotics to cover the insertion procedure.

Pain relief

You may feel pain during and after the fitting. We would suggest that you take some painkillers about an hour before you have the IUS fitted.

Contraception

It is important to have prior alternate contraception arranged in case the device cannot be fitted.

What happens during the IUS fitting?

Your appointment will last 20–30 minutes. We will check that you have understood all the information provided and you will be asked to sign a consent form.

The doctor will examine you internally to check the position and size of your uterus before inserting your coil. You may be offered swabs/a smear at the same time.

Before you leave, you will see the nurse and be given an aftercare leaflet. You may want to bring a chaperone as some women experience cramps and slight bleeding after the procedure.

If you have any further questions, please phone the surgery to arrange a telephone consultation with the well woman nurse or your own GP.