Mirena® frequently asked questions
What is an ‘Intrauterine System’ (IUS)?
How effective is Mirena?
How does Mirena work?
What side effects can I expect?
How is Mirena fitted?
What does Mirena cost?
What is an ‘Intrauterine System’ (IUS)?
Mirena is an ‘Intrauterine System’ (IUS) this is not the same as an ‘Intrauterine Device’ (IUD). An ‘IUD’ is a contraceptive device with a small plastic frame with copper wire wrapped around the plastic. A nylon thread is attached to the end to assist with removal. Sometimes called a ‘coil’, it’s 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 called an IUS to distinguish it from the copper IUD, although it is also fitted into your uterus. It also has a small plastic frame but is different because it contains a hormone and no copper. In addition to being a very effective contraceptive, Mirena treats heavy menstrual bleeding, making your periods shorter, lighter and less painful. Mirena is also quite often prescribed for women in their peri-menopausal years as part of their hormone replacement therapy (HRT) to provide protection to the lining of the uterus (the endometrium).
How effective is Mirena?
Mirena is one of the most effective contraceptive methods available. Once Mirena is properly fitted, it is effective for up to 5 years and the reliability remains over 99% over this time.
How does Mirena work?
Once inserted, Mirena releases a very small amount of the hormone 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 conception in 3 key ways:
- It thickens the normal mucus in the cervical canal (opening of the uterus) so that the sperm cannot enter the uterus to fertilise the egg
- It inhibits the normal sperm function and movement inside the uterus and fallopian tubes preventing fertilisation
- It reduces the monthly growth of the lining of the uterus, which also makes your period lighter and shorter.
What side effects can I expect?
The most common side effect is a change in your menstrual bleeding pattern. As the level of hormone in the woman’s blood stream is very low, the 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.
How is Mirena fitted?
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.
What does Mirena cost?
The cost of Mirena is around $310-$360, which is approximately $5.00 per month over the 5 years that Mirena usually provides contraceptive protection for. In addition to the cost for Mirena you will need to pay the doctor’s fees for the insertion of Mirena.
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.