Mirena 20 micrograms/24 h intrauterine system – levonorgestrel for contraception and heavy periods

Mirena is an intrauterine delivery system (IUS, also known as a “hormonal coil”) that is placed in the womb and slowly releases the hormone levonorgestrel – a progestogen. One system contains 52 mg levonorgestrel, with an initial release of 20 micrograms per 24 hours. Mirena has a T-shaped body with two thin removal threads.

Mirena is used as effective, long-term and reversible contraception, to reduce heavy menstrual bleeding and, in menopausal women, to protect the womb lining during oestrogen hormone replacement therapy (HRT). The system may only be inserted and removed by a doctor, and in Serbia it is used in healthcare institutions.

What is Mirena (levonorgestrel) used for and how is it used?

Key facts about the medicine

What is Mirena used for?

According to the official leaflet, Mirena is used:

• as an effective, long-term and reversible method of contraception,
• to reduce heavy menstrual bleeding (idiopathic menorrhagia),
• in menopausal women, together with an oestrogen medicine as part of hormone replacement therapy, to protect the womb lining from excessive growth.

As a contraceptive, levonorgestrel prevents thickening of the womb lining, thickens the mucus in the cervix so sperm cannot pass easily, and in some women prevents ovulation. Mirena is not intended for use before the first menstrual period.

How is it used and dosed?

Mirena is inserted only by a doctor after a gynaecological examination excluding pregnancy and sexually transmitted diseases (and a breast examination if needed). Genital infections must be treated before insertion.

• Protection against pregnancy starts immediately after insertion; the chance of pregnancy in the first year is about 2 in 1,000 women.
• The first check-up is 6 weeks after insertion and further visits are set by the doctor; after insertion you receive a Patient Reminder Card to bring to visits.
• You can check the system is in place by gently feeling the two threads in the vagina (e.g. in the shower) – do not pull them.
• If you do not want to become pregnant, removal should take place in the first 7 days of the cycle; otherwise use a condom for 7 days before removal. Fertility returns quickly after removal.

Special patient groups

• Adolescents: Mirena is not indicated before the first period (menarche).
• Postmenopause (HRT): the doctor reassesses the need for therapy at least once a year; with HRT the system is removed after 4 years.
• After childbirth: insertion is postponed for at least 6 weeks; the risk of perforation is higher in breastfeeding women and when inserted up to 36 weeks after delivery.
• Liver disease: a liver tumour or acute/severe liver disease is a contraindication.
• Kidney function: use in kidney impairment has not been studied.

Contraindications – when the medicine must not be used

Mirena must not be used if:

• you are pregnant or suspect pregnancy,
• you have or have had any type of cancer or cancer is suspected (including breast, womb and cervical cancer; leukaemia unless in remission),
• you have current or recurrent pelvic inflammatory disease, cervicitis or a genital infection,
• you have had an infection of the womb after childbirth or termination of pregnancy in the last 3 months,
• you have a condition that increases susceptibility to infections,
• you have cervical changes (abnormal smear/dysplasia) or undiagnosed vaginal bleeding,
• you have an abnormality of the womb or fibroids that distort the uterine cavity,
• you have a liver tumour or other acute or severe liver disease,
• you have recent trophoblastic disease with raised hCG,
• you are hypersensitive to levonorgestrel or any component of the system.

As part of HRT, Mirena must not be used if you have had a stroke, heart attack or other serious heart or arterial disease.

Precautions and warnings

• Consult your doctor if you have migraines (especially with visual disturbance), jaundice, high blood pressure, diabetes (glucose tolerance may be affected), previous blood clots, arterial disease, a previous ectopic pregnancy or ovarian cysts, or are on long-term steroid therapy.
• Depression and depressed mood have been reported with hormonal contraception, including Mirena; report mood changes to your doctor promptly.
• Pain, bleeding and fainting may occur during insertion; in epilepsy there is a rare possibility of a seizure – tell the doctor.
• The system may be expelled spontaneously (more likely with obesity or previous heavy periods) – it then no longer protects against pregnancy.
• Smoking is not recommended while using hormonal medicines.

Interactions with other medicines, alcohol and food

The effect of hormonal contraceptives may be reduced by medicines that increase liver enzyme activity. Tell your doctor if you use:

• medicines for epilepsy,
• antifungals (e.g. griseofulvin, fluconazole, itraconazole, ketoconazole, voriconazole),
• certain antibiotics (rifampicin, macrolides – clarithromycin, erythromycin),
• medicines for HIV or hepatitis C (protease inhibitors, non-nucleoside reverse transcriptase inhibitors),
• barbiturates,
• medicines for angina and/or high blood pressure,
• St John’s wort products.

Food and drink do not affect the use of Mirena.

Pregnancy and breastfeeding

Mirena must not be used during pregnancy. If you have no period for 6 weeks, do a pregnancy test. If you become pregnant with Mirena in place, contact your doctor immediately – an ectopic pregnancy must be excluded, and both removing and leaving the system carry a risk of miscarriage and premature birth.

Very small amounts of the hormone have been found in breast milk (less than with other hormonal methods); ask your doctor before breastfeeding.

Driving and using machines

Mirena is not known to affect the ability to drive or use machines.

Possible side effects

Side effects are most common in the first months after insertion and decrease over time:

• Very common (more than 1 in 10): vaginal bleeding and spotting; absent, scanty or infrequent periods.
• Common (up to 1 in 10): ovarian cysts, painful periods, weight gain, depression, nervousness, headache, migraine, dizziness, abdominal, pelvic or back pain, nausea, acne, increased body hair, reduced libido, increased vaginal discharge, vulvovaginitis, breast tenderness, expulsion of the system.
• Uncommon (up to 1 in 100): uterine perforation, genital infections, endometritis, cervicitis, swelling of the abdomen and legs, hair loss, itching and eczema, chloasma.
• Rare (up to 1 in 1,000): rash. Not known: allergic reactions, increased blood pressure.

Breast cancer has been reported in Mirena users, but the risk and frequency are unknown; check your breasts regularly and see a doctor if you feel a lump.

Overdose, missed dose and stopping treatment

• Overdose, missed dose and sudden stopping: not applicable according to the leaflet – the system releases the hormone continuously.
• Removal: the doctor can remove Mirena at any time; if you do not want pregnancy, use another method for 7 days before removal or have a new system inserted immediately.
• If the system falls out or you cannot feel the threads, use a condom and contact your doctor.

Composition, packaging and manufacturer

• Active substance: levonorgestrel, 52 mg per system; initial release 20 micrograms/24 h.
• Excipients: polydimethylsiloxane elastomer; polydimethylsiloxane tubing (contains colloidal anhydrous silica); polyethylene; barium sulphate (makes the body visible on X-ray); black iron oxide (E172).
• Appearance: white T-shaped body with a loop and two arms, a hormone cylinder and brown removal threads; the system sits at the tip of the inserter.
• Pack: sterile system with integrated inserter in an APET/PE or PETG/PE blister, in a carton with a package leaflet.
• Marketing authorisation holder: BAYER d.o.o. Belgrade, Omladinskih brigada 88b, Belgrade, Serbia.
• Manufacturers: Bayer Oy, Turku, Finland; Bayer, farmacevtska družba d.o.o., Ljubljana, Slovenia.
• Authorisation number: 515-01-02212-21-001 of 11 May 2022.

Storage

• No special storage conditions are required.
• Keep out of the sight and reach of children.
• Do not use after the expiry date stated on the pack.

Frequently asked questions

How long does Mirena protect against pregnancy?

According to the leaflet approved in Serbia, Mirena is effective for 5 years for contraception and heavy menstrual bleeding, after which it is removed or replaced with a new system. When used with oestrogen HRT, it is removed after 4 years.

Is spotting or a missed period normal after Mirena is inserted?

Yes. Irregular bleeding and spotting are very common in the first months, and bleeding usually becomes lighter over time; in some women periods stop completely. If you have no period for 6 weeks, do a pregnancy test; severe pain or heavy prolonged bleeding need an examination.

How do I know Mirena is in place?

Gently insert a finger into the vagina and feel for the two thin threads at the lower end of the system – do not pull them. If you cannot feel the threads, or you can feel the system itself, use a condom and see your doctor.

When can I get pregnant after Mirena is removed?

Fertility returns quickly after removal. Studies show that women who stop using it to conceive have the same pregnancy rate within a year as women not using contraception.

Does Mirena protect against sexually transmitted infections?

No. Mirena prevents pregnancy but does not protect against sexually transmitted infections. Genital infections must be treated before insertion, and condoms are needed for protection against infections.

Related information

For additional care and support with contraception, see also the Condoms category – products in this category do not replace the medicine you have been prescribed.

Sources

• ALIMS – Package leaflet Mirena®, 20 micrograms/24 h, intrauterine delivery system (May 2022, Serbian)
• ALIMS – SmPC Mirena®, 20 micrograms/24 h, intrauterine delivery system (Serbian)

Sources checked on: 23 October 2026.