The most common medications that are used for medication abortions are mifepristone and misoprostol. First, a doctor gives the woman mifepristone, which is sometimes also called "RU-468" or "the abortion pill". This drug blocks the hormone progesterone in the body. Without progesterone, the embryo cannot survive. The lining of the uterus becomes thinner, and the embryo cannot grow or stay attached to the lining of the uterus. After a few days, a doctor gives the woman misoprostol. This makes the uterus contract (or get smaller) and the embryo is expelled from (or pushed out of) the uterus through the woman's vagina. Sometimes, another medication, called methotrexate, is used along with misoprostol in medication abortions. A woman is given methotrexate, usually as a shot in a doctor's office, and the drug stops the embryo from staying attached to the lining of the uterus. Then misoprostol is given a few days later.