What is Mirena?
Mirena is a small device that is fitted into the uterus, where it releases a hormone called progesterone.
It can be used:
- to treat abnormal bleeding
- to reduce pain associated with periods
- to protect the uterine lining during hormone therapy
- for contraception
- to manage endometrial symptoms
- in the management of polycystic ovarian syndrome.
When it is used to treat abnormal bleeding your doctor may first recommend some tests to ensure there is nothing wrong with the lining of your uterus.
How does it work?
Mirena is a thin plastic T-shaped device containing levonorgestrel which is a synthetic form of the female hormone known as progesterone. Progesterone is a hormone found in other preparations, including the oral contraceptive pill. This hormone reduces the monthly growth of the lining of the uterus (endometrium) and therefore reduces the heaviness of periods. It also affects sperm motility.
How is the Mirena inserted?
The procedure can be performed in the outpatient clinic without any anaesthesia. It is inserted in a process similar to the taking of a pap smear. The procedure itself takes approximately five minutes. It can also be performed at the time of another gynaecological procedure under anaesthetic.
Following insertion, you will not be able to feel the device and it is not something you or your partner would normally feel during sex but you should be able to feel the threads of the device with your fingers. The device is removed in a procedure similar to the insertion.
All women who have a Mirena inserted will be contacted by phone at three and six months post insertion to ensure ongoing satisfaction with the device. Should you have any concerns at either of these contact times, an outpatient appointment can be easily arranged.
How long does the Mirena last?
The device stays in the uterus and remains effective for five years, but may be removed sooner if desired. Fertility returns rapidly after removal. The device does not dissolve and must be removed.
How effective is the Mirena?
Mirena is extremely effective in managing gynaecological conditions, such as heavy and/or painful periods, pelvic pain and endometriosis. A recent audit conducted at Mater showed that, when inserted for pelvic pain, up to 90 per cent of women had significant improvement of their symptoms. More than 70 per cent of women, who have it inserted to help with heavy periods, find their periods are significantly lighter. About 30 per cent of women find they stop having periods altogether after a few months, which is quite safe. While it is very effective at preventing pregnancy, no contraceptive method is 100 per cent reliable. Each year one to two women per thousand, using a Mirena, can expect to fall pregnant.
What are the disadvantages of a Mirena?
- It does not prevent sexually transmitted diseases
- It does not suit women who have a uterus with an unusual shape as it is more likely to be expelled
- After insertion bleeding irregularities are very common. Most women will experience spotting daily for the first six weeks. This is normal and settles soon after.
When should the Mirena be inserted?
Mirena is best inserted within seven days of the first day of your period. That way it is not inserted when a woman might be pregnant and it is also easier at that time as the cervix is open a little more.
What are the complications of this procedure?
Risk, side effects and complications include the following, but are not limited to:
- at the time of insertion
- discomfort at the time of and immediately after insertion—we would recommend you take simple pain relief before leaving home, on the day of your procedure, to help reduce the discomfort of insertion
- introduction of infection (less than 1 in 100 women)
- perforation of the uterus (less than 1 in 100 women)
- menstrual control– you can expect some change in your periods but—the exact effect is difficult to predict. Most women will stop having periods, and for the remainder, periods will become lighter or less regular. In some instances, periods may be very light, but prolonged.
- expulsion– rarely, the device may be expelled during the menstrual period (<3%). Check for the threads of the device after each period or about once a month
- other effects– very small amounts of this drug are absorbed into your circulation so hormonal symptoms are uncommon, minor and self-limiting such as headaches, breast tenderness, and changes in libido.
Any other specific risks and complications will be discussed prior to the procedure.
All women who have the device inserted will have a phone consultation as part of routine follow up at three and six months post insertion.
However, please contact either your General Practitioner (GP) or Mater Hospital Brisbane Emergency Department on 07 3163 8111 if you experience any of the following after insertion of the Mirena:
- a fever or are feeling unwell
- offensive vaginal discharge or heavy bleeding
- nausea and vomiting which does not settle
- severe pain
© 2014 Mater Misericordiae Ltd. ACN 096 708 922
Mater acknowledges consumer consultation in the development of this patient information.
Mater Doc Num: HOSP-002-01186
Last modified 06/11/2015.