Overview

Mirena is a hormonal intrauterine device (IUD) that can provide long-term birth control (contraception).

The device is a T-shaped plastic frame that's inserted into the uterus, where it releases a type of the hormone progestin. To prevent pregnancy, Mirena:

• Thickens mucus in the cervix to stop sperm from reaching or fertilizing an egg
• Thins the lining of the uterus and partially suppresses ovulation

Mirena prevents pregnancy for up to five years after insertion. It's one of several hormonal IUDs with Food and Drug Administration approval.