What is Mirena?

MIRENA
(LEVONORGESTREL-RELEASING INTRAUTERINE SYSTEM)

MIRENA is a hormone-releasing system placed in your uterus to prevent pregnancy for up to 5 years.

MIRENA is T-shaped. It contains a hormone called levonorgestrel. Levonorgestrel is a progestin hormone often used in birth control pills. MIRENA releases the hormone into the uterus. Only small amounts of the hormone enter your blood.

Two brown threads are attached to the stem of the T. You can check that MIRENA is in place by feeling for the threads at the top of your vagina with your fingers. Your healthcare provider can also remove MIRENA at any time by pulling on the threads. The threads are the only part of MIRENA you can feel when MIRENA is in your uterus.

HOW DOES MIRENA WORK?

There is no single explanation of how MIRENA works. It may stop release of your egg from your ovary, but this is not the way it works in most cases. It may block sperm from reaching or fertilizing your egg. It may make the lining of your uterus thin. We do not know which of these actions is most important for preventing pregnancy and most likely all of them work together.