Intrauterine devices (IUD) for heavy periods

Sounds like 'Mi·RAY·na'

Key points about intrauterine devices (IUD) for heavy periods

  • Intrauterine device (IUD) used for the treatment of heavy periods or excessive menstrual bleeding (also called menorrhagia) and for the treatment of endometriosis.
  • Intrauterine device (IUD) is also called Mirena®. It is used for the treatment of heavy periods or excessive menstrual bleeding.
  • Find out how it is inserted and possible side effects.
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Mirena® is an intrauterine device (IUD) used for the treatment of heavy periods or excessive menstrual bleeding (also called menorrhagia) and for the treatment of endometriosis. IUDs are often used for contraception to prevent pregnancy, but Mirena is also used as a treatment for heavy or painful periods, even in women who do not actually need contraception. 

Note: This information is about Mirena for heavy periods and endometriosis. For information about Mirena for contraception, see IUDs for contraception

Mirena is a small, white T-shaped plastic device with 2 removal threads that is placed inside your womb (uterus). It slowly releases the hormone progestogen (as levonorgestrel) directly onto the lining of your womb. This makes the lining of your womb thinner, making you less likely to have menstrual bleeding and reducing heavy periods. Once fitted, Mirena lasts for up to 5 years. You do not need an operation or a general anaesthetic to have it inserted. It can be done at your GP clinic.

It can take a few months for Mirena to have its full effect, but by 6 months after placement, most women will have only light bleeding and sometimes no bleeding at all. The total blood loss per cycle slowly decreases with continued use.

The number of spotting and bleeding days may increase when you first have it inserted but then these usually decrease in the months that follow. Bleeding may also be irregular.   

Mirena® is unsuitable in women who have:

  • pelvic infection
  • cancer of the breast, uterus (womb), cervix or ovary
  • a history of a heart attack or stroke
  • blood clotting problems such as deep vein thrombosis
  • liver disease.

Like all medicines Mirena can cause side effects, although not everyone gets them.

Side effects What should I do?
  • Pain
  • Dizziness
  • Feeling weak, feeling faint
  • This can occur after Mirena is inserted.
  • If these symptoms continue for more than a day, contact your doctor.  
  • Heavy, painful periods that last longer than usual
  • Breast tenderness, pain or swelling
  • This tends to be in the first few months after insertion of Mirena and often settles with time.
  • If troublesome, ongoing or if your are worried, discuss with your doctor or nurse.

  • Signs of pelvic inflammatory disease such as pain in your lower abdomen or stomach area, fever, flu-like symptoms, feeling unwell, dizziness, feeling faint or vaginal discharge
  • There is a small risk of pelvic inflammatory disease especially within the first 20 days after insertion.
  • Tell your doctor or nurse immediately or phone HealthLine 0800 611 116.    
  • Weight gain or fluid retention (bloating)
  • Depression or nervousness
  • Contact your doctor or nurse or phone HealthLine 0800 611 116.
  • Migraine or severe headaches or increased blood pressure
  • Contact your doctor or nurse or phone HealthLine 0800 611 116.
  • Risk of expulsion (the IUD coming out by itself)
  • The IUD may come out by itself, because of muscular contractions of your womb.
  • Tell your doctor if you think this has happened.
  • Risk of perforation (a small hole in your womb lining)
  • This is a very rare (1 in 1000) complication of Mirena that can happen at the time of fitting.
  • The risk of is higher in breastfeeding women or in women up to 36 weeks after birth.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product(external link)

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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