There are two types of medications used for medical abortion, the clinically used ones being Mifepristone and Misoprostol. Mifepristone is able to block the activity of progesterone in the woman’s body, and its affinity for the endometrial progesterone receptor is five places higher than that of progesterone in the woman’s body, which enables it to block the activity of progesterone and lead to the termination of pregnancy. Additionally after termination of pregnancy the meconium becomes necrotic and releases endogenous prostaglandin substances that induce uterine contractions and softening of the cervix. Misoprostol has a more pronounced contractile effect on the pregnant uterus, and these two drugs used together are more effective in fighting early pregnancy in women less than 49 days pregnant.