How it works Mifepristone blocks receptors of progesterone, a key hormone in establishing and maintaining a pregnancy. It prevents the fertilized egg from adhering to the uterus. A few days after taking Mifepristone, the woman takes a second drug, Misoprostol, which causes uterine contractions and bleeding. The combination terminates the pregnancy. Within 48 hours of taking Mifepristone, women return to their doctor to receive Misoprostol.
Most women complete the abortion within six hours of taking the second drug.
For a small percentage of women, the process takes up to a week to complete. Two weeks after taking Misoprostol, the women return to their doctor for an ultrasound to verify the abortion was completed. Side effects of medical abortion with Mifespristone have included extensive bleeding, nausea, vomiting, and diarrhea. A small percentage of women who used the method required blood transfusions or the drug combination didn't terminate the pregnancy and surgical abortion was required. Side effects include uterine cramping, heavy bleeding, nausea, and fatigue.