Description
Mirena is a form of female contraception that works by slowly and evenly releasing levonorgestrel (a hormone) into the uterine cavity. Mirena is effective for up to five years. The mechanism by which levonorgestrel prevents pregnancy works by thickening the cervical mucus so as to impede the passage of sperm into the uterus, inhibiting sperm capacitation or survival, and altering the endometrium.
