POM: Prescription only medicine
The Patient Information Leaflet (PIL) is the leaflet included in the pack with a medicine. It is written for patients and gives information about taking or using a medicine. It is possible that the leaflet in your medicine pack may differ from this version because it may have been updated since your medicine was packaged.
Below is a text only representation of the Patient Information Leaflet. The original can be viewed in PDF format using the link above.
The text only version may be available from RNIB in large print, Braille or audio CD. For further information call RNIB Medicine Leaflet Line on 0800 198 5000. The product code(s) for this leaflet is: PL00010/0547.
Due to regulatory changes, the content of the following Patient Information Leaflet may vary from the one found in your medicine pack. Please compare the 'Leaflet prepared/revised date' towards the end of the leaflet to establish if there have been any changes.
If you have any doubts or queries about your medication, please contact your doctor or pharmacist.
Date of insertion = X Spotting = ○ Bleeding = ●
20 micrograms/24 hours intrauterine delivery system
Patient Information Booklet
Date of Fitting:
First check-up visit:
About this booklet
Please read this booklet carefully before you decide to have Mirena fitted.
It provides you with some useful information about Mirena. The information in this booklet applies only to Mirena. If you have any questions or are not sure about anything, please ask your doctor or nurse.
In this booklet:
1. What Mirena is and what it is used for page number
2. Before you have Mirena fitted page number
3. How and when Mirena is used page number
4. Possible side effects page number
5. Further information page number
1. What Mirena is and what it is used for
Mirena is an intrauterine system (IUS) placed inside the womb (uterus) where it slowly releases the hormone levonorgestrel. It can be used in the following three ways:
1. As an effective long-term and reversible method of contraception.
2. For reducing menstrual blood flow, if you suffer from heavy periods (heavy menstrual bleeding).
It can be used for contraception and heavy menstrual bleeding until it is removed or up to a maximum of 5 years.
3. If you are going through the menopause Mirena can be used in conjunction with an oestrogen as part of a hormone replacement therapy (HRT) regimen to protect the lining of your womb.
Not so much is known about how well Mirena protects the lining of the womb beyond 4 years of use in women who are taking oestrogen to treat menopausal symptoms.
Therefore, if you are using it in this way, your doctor or nurse will remove your Mirena after 4 years. Your doctor will be able to advise you further.
Children and adolescents
Mirena is not indicated for use before the first menstrual bleeding (menarche).
How does Mirena work?
As a contraceptive:
The hormone in Mirena prevents pregnancy by:
There are also some effects on the lining of the womb caused by the presence of the T-shaped frame of the Mirena device.
In the treatment of heavy menstrual bleeding:
The hormone in Mirena reduces menstrual bleeding by controlling the monthly development of the womb lining, making it thinner, so that there is less bleeding every month.
As part of an HRT regimen:
The menopause is a gradual process which usually takes place between the ages of about 45 and 55. Although the menopause is natural, it often causes distressing symptoms such as hot flushes and night sweats. These symptoms are due to the gradual loss of the female sex hormones (oestrogen and progestogen) produced by the ovaries.
Oestrogens can be used to relieve the menopausal symptoms. However, taking oestrogens alone increases the risk of abnormal growth or cancer of the lining of the womb. Taking a progestogen, such as the hormone in Mirena (levonorgestrel), as part of an HRT regimen lowers this risk by protecting the lining of the womb.
2. Before you have Mirena fitted
Your doctor or nurse will carry out some tests before you have Mirena fitted to make sure that it is suitable for you to use. This will include a pelvic examination so that pregnancy and sexually transmitted diseases can be excluded and may also include other examinations such as a breast examination, if your doctor or nurse feels this is appropriate.
Genital infections will need to be successfully treated before you can have Mirena fitted.
If Mirena is to be fitted for HRT use your doctor will firstly carry out an assessment of your symptoms to ensure that treatment is only initiated for symptoms that adversely affect your quality of life. Such an assessment should be repeated by your doctor at least annually. You should also consult the Patient Information Leaflet of the oestrogen product that is to be used in conjunction with Mirena before starting your HRT regimen as there are some important risk factors associated with HRT that you should consider, such as the risk of endometrial cancer, breast cancer and blood clots. You may feel pain or have some bleeding during insertion.
If you have epilepsy, tell the doctor or nurse fitting the Mirena because, although rare, a fit can occur during insertion. Some women might feel faint after the procedure. This is normal and your doctor or nurse will tell you to rest for a while.
Do not use Mirena and please tell your doctor or nurse if you:
Mirena must not be used as part of an HRT regimen if you have had a stroke, heart attack or any heart problems.
Mirena may not be suitable for all women.
Consult your doctor or nurse if you:
You may still be able to use Mirena if you have or have had some of these conditions. Your doctor or nurse will advise you.
You must also tell your doctor or nurse if any of these conditions occur for the first time while you have Mirena in place.
You must see a doctor or nurse as soon as possible if you develop painful swelling in your leg, sudden chest pain or difficulty breathing as these may be a sign of a blood clot. It is important that any blood clots are treated promptly.
You must also see a doctor without delay if you develop persistent lower abdominal pain, fever, pain during sexual intercourse or abnormal bleeding. If you get severe pain or fever shortly after Mirena has been inserted, you may have a severe infection which must be treated immediately.
It is advisable to give up smoking when using hormone containing products such as Mirena.
Can I change my mind?
Your doctor or nurse can remove Mirena at any time. Unless you wish to get pregnant the removal should be carried out during the first 7 days of your period. Otherwise it is important to use another form of contraception (e.g. condoms) in the 7 days leading up to the removal as intercourse during this week could lead to pregnancy after Mirena is removed.
If you do wish Mirena to be removed so that you can get pregnant your usual level of fertility is expected to return after it is removed. Studies have suggested that in women who discontinue Mirena (in order to become pregnant) the pregnancy rate at one year is similar to those who do not use contraception.
Taking other medicines
The effect of hormonal contraceptives such as Mirena may be reduced by medicines that increase the amounts of enzymes made by the liver. Please tell your doctor or nurse if you are taking any:
Please tell your doctor or nurse if you are taking or have recently taken any other medicines, including medicines obtained without prescription.
Pregnancy and breastfeeding
Mirena should not be used during pregnancy or if you think you are pregnant.
It is very rare for women to become pregnant with Mirena in place.
Missing a period may not mean that you are pregnant as some women may not have periods at all while using Mirena. However, in order to exclude the possibility of pregnancy, you should consider a pregnancy test if you have not had a period for 6 weeks. If this test is negative there is no need to carry out another test, unless you have other signs of pregnancy, e.g. sickness, tiredness or breast tenderness.
If you do become pregnant with Mirena in place, please contact your doctor as soon as possible so that ectopic pregnancy can be excluded and Mirena removed to reduce the risk of spontaneous abortion.
Very small amounts of the hormone in Mirena are found in breast milk but the levels are lower than with any other hormonal contraceptive method. Please ask your doctor or nurse for advice before breastfeeding.
3. How and when Mirena is used
Only a doctor or specially trained nurse can fit Mirena. They will explain the fitting procedure and any risks associated with its usage. You will then be examined by your doctor or nurse before Mirena is fitted. If you have any concerns over its usage you should discuss it with them.
When Mirena is fitted for contraception or heavy menstrual bleeding: Mirena should be inserted either during your period or within seven days from the beginning of your period. If you already have Mirena and it is time to replace it with a new one, you do not need to wait until your period. If you have just had a baby, you should wait at least 6 weeks before having Mirena fitted (see section 4 “Possible side effects – Severe pain and continued bleeding”). Mirena can sometimes be fitted immediately after you have had an abortion, provided that you have no genital infections.
When Mirena is fitted for HRT use: If you no longer have periods then Mirena can be inserted at any time. If you still have periods, Mirena should be inserted during the last days of bleeding. Remind your healthcare provider that you have Mirena inserted, especially if they were not the person who inserted it.
How quickly does Mirena work?
You are protected from pregnancy as soon as Mirena is fitted. The possibility of becoming pregnant is approximately 2 in 1,000 in the first year. The failure rate may increase in case of the Mirena coming out by itself (see page XX ) or perforation (see page XX ‘Side Effects’).
Heavy menstrual bleeding:
Mirena usually results in lighter periods after 3 to 6 months of treatment.
The hormone in Mirena will begin to protect the lining of your womb as soon as it is fitted.
How often should I have Mirena checked?
You should have it checked 6 weeks after it is fitted. Your doctor may determine how often and what kind of check-ups are required in your particular case.
How can I tell whether Mirena is in place?
Gently put a finger into your vagina and feel for the two thin threads attached to the lower end of Mirena. Your doctor or nurse will show you how to do this.
Do not pull the threads because you may accidentally pull it out. If you cannot feel the threads, contact your doctor or nurse as soon as possible and in the meantime avoid intercourse or use a barrier contraceptive (such as condoms). The threads may have simply drawn up into the womb or cervical canal. If the threads still cannot be found by your doctor or nurse, they may have broken off, or Mirena may have come out by itself, or in rare cases it may have perforated the wall of your womb (uterine perforation, see section 4). It may be necessary for you to have an ultrasound scan or x-ray to locate Mirena.
Contact your doctor or nurse if you can feel the lower end of Mirena itself or you or your partner feel pain or discomfort during sexual intercourse.
What happens if Mirena comes out by itself?
If it comes out either completely or partially you may not be protected against pregnancy.
It is rare but possible for this to happen without you noticing during your menstrual period. An unusual increase in the amount of bleeding during your period might be a sign that this has happened. Tell your doctor or nurse if there are any unexpected changes in your bleeding pattern.
How will Mirena affect my periods?
Mirena will affect your menstrual cycle.
For all uses of Mirena:
You may have lighter periods or painful periods or some spotting (light bleeding in between periods) and irregular bleeding during the first few months after Mirena is fitted.
You may have prolonged or heavy bleeding or an increase in the frequency of bleeding, usually in the first 2 to 3 months, before a reduction in blood loss is achieved.
Overall you are likely to have fewer days bleeding in each month and you might eventually have no periods at all. This is due to the effect of the hormone (levonorgestrel) on the lining of the womb.
If you have had Mirena fitted for heavy menstrual bleeding:
You should have lighter periods after 3 to 6 months. If you do not have lighter periods after 3 to 6 months, alternative treatments should be considered.
If you have had Mirena fitted for HRT use:
If you have had Mirena fitted for quite a long time and then start to have bleeding problems, it is important that you contact your doctor so that tests can be carried out to exclude changes to your womb.
There is a calendar on the last page of this patient information booklet. Your doctor or nurse may ask you to fill this in to check your pattern of bleeding. If you are asked to do so, mark the date of insertion with an “X” in the appropriate date square. Mark days of spotting with “o” and bleeding with “•”.
4. Possible side effects
Taking any medicine carries some risk of side effects. With Mirena these are most common during the first months after it is fitted and decrease as time goes on.
If you experience any of the following serious side effects please contact your doctor or nurse immediately:
Very Common (more than 1 in 10 women)
Common (less than 1 in 10 women)
Uncommon (less than 1 in 100 women)
Rare (less than 1 in 1000 women)
Your partner may feel the removal threads during intercourse.
Every woman is at risk of breast cancer, but it is rare in women under the age of 40. Breast cancer has been reported in Mirena users, although the risk and frequency are unknown.
In pre-menopausal women, the frequency of developing breast cancer whilst using Mirena is possibly similar to that associated with using Combined Oral Contraceptives, but the evidence for this is less conclusive.
In post-menopausal women, using hormone replacement therapy (HRT) slightly increases the risk of breast cancer. Although the risk of developing breast cancer is higher with combined oestrogen/progestogen HRT, than with oestrogen-only HRT, the risk of breast cancer developing when Mirena is prescribed to provide the progestogen component of HRT is not yet known. The patient information leaflet of the oestrogen component of the treatment should also be consulted for additional information.
It is important to regularly check your breasts and you should contact your doctor if you feel any lump in your breasts. You should also tell your doctor if a close relative has or ever had breast cancer.
If any of the side effects gets serious, or if you notice any side effects not listed in this booklet, please tell your doctor or nurse.
Reporting of side effects
If you get any side effects talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly (see details below).
By reporting side effects you can help provide more information on the safety of this medicine.
or search for MHRA Yellow Card in the Google Play or Apple App Store.
5. Further Information
What Mirena contains
Mirena contains 52 milligrams of levonorgestrel. The hormone is contained within a substance called polydimethylsiloxane. This is surrounded by a membrane (skin) also made of polydimethylsiloxane.
The Mirena T-shaped frame also contains barium sulphate so that it can be seen on X-rays.
What Mirena looks like and contents of the pack
Mirena consists of a small white T-shaped frame made from a plastic called polyethylene.
There are two fine brown threads, made of iron oxide and polyethylene, attached to the bottom of the frame. These allow easy removal and allow you or your doctor or nurse to check that Mirena is in place.
Each sterile pack contains one Mirena and should not be opened until required.
Product Licence Holder:
PL Number: 00010/0547
Mirena is manufactured by:
This booklet was revised February 2018.
PIL v 025_0