Mirena is an ‘Intrauterine System’ (IUS) which means that Mirena is fitted into your uterus. It has a small plastic frame and contains a hormone but no copper. Mirena is a very effective contraceptive and can also treat heavy menstrual bleeding, following appropriate investigation where the cause is not identified. Mirena may make your periods shorter and lighter than before treatment. Mirena can also be prescribed for women in their perimenopausal years as part of their hormone replacement therapy (HRT) to provide protection to the lining of the uterus (the endometrium).
Mirena is different from an ‘IUD’ sometimes called a ‘coil’ which is a contraceptive device on a small plastic frame with copper wire wrapped around the plastic. A coil is very effective at preventing pregnancy but a problem you may experience with this method is that it may make your periods heavier and more painful.
Mirena is one of the most effective and reliable methods of contraception available. Studies have shown that if 1000 women use the system for 1 year, no more than 2 are likely to become pregnant. This is comparable to female sterilisation. Once your system is properly fitted, it is effective for up to 5 years and the reliability remains over 99% during this time.
Mirena has a special membrane on the hormone sleeve that allows the release of a very small amount of the hormone levonorgestrel into your uterus at a constant rate, meaning the levels remain stable throughout the day. The local release means that the hormone is released where it needs to work.
The hormone in Mirena prevents pregnancy in 3 key ways
As the level of hormone in the woman’s blood stream is very low, hormonal side effects are generally mild in nature and more common in the first few months of use. If hormonal side effects occur, they usually settle after a few months but if you are concerned please talk to your Doctor.
The majority of women experience changes in menstrual bleeding pattern after insertion of Mirena. Reported changes have included increased and decreased menstrual bleeding, spotting, infrequent or light periods and no periods.
Some other common side effects reported by women using Mirena include:
Your Doctor should advise you of the risks, other potential side effects and possible benefits.
Only a Doctor can fit Mirena. After a gynaecological examination an instrument called a speculum is inserted into the vagina and the cervix (opening of the uterus) is cleaned with an antiseptic solution. Mirena is fitted into the uterus via a thin, flexible plastic tube. The threads pass from the system through the cervix and into the vagina. The threads are then cut to about 2 to 3 cm in length, outside the cervix.
Mirena is funded for women who suffer from heavy menstrual bleeding (HMB) and who meet the PHARMAC Special Authority Criteria. Even if you meet the funding criteria for HMB you will still need to pay the doctor’s fees for Mirena to be fitted.
If you don’t meet the criteria for PHARMAC funding for heavy menstrual bleeding or if you wish to have a Mirena fitted for contraceptive purposes, or as part of hormone replacement therapy, you will need to pay for the device and doctors’ fees for the Mirena to be fitted. Speak to your doctor or Family Planning Clinic for more information. Costs can vary.