Mirena is a small T-shaped plastic frame that is inserted into the womb (uterus). It slowly releases the hormone levonorgestrel for 5 years or until it is removed. It is a type of IUD, or intra-uterine device.
Mirena may be used as a long-term, reversible contraceptive. It prevents pregnancy in a few ways, including thickening cervical mucus so that the sperm cannot reach the egg. Mirena also thins the womb lining.
Mirena may be used to treat very heavy period bleeding or to prevent excessive growth of the womb lining during hormone replacement therapy. It works by stopping the growth of the womb lining, which reduces the amount and duration of bleeding.
Mirena must be inserted or removed by a doctor trained in using it.