How Abortion Works

By: Molly Edmonds

Medical Abortion

There are two methods for performing an abortion: medical and surgical. In medical abortions, the fetus is expelled when an abortifacient, or abortion-inducing substance, is administered. Abortifacients have a long history; since the time of Ancient Greece, women have tried to induce an abortion by swallowing a mix of herbs or plants. However, the drugs used to induce to induce a medical abortion are fairly new, having only been approved by the Food and Drug Administration (FDA) in 2000.

The regimen approved by the FDA is 600 milligrams of mifepristone followed by 400 micrograms of misoprostol. The administration of mifepristone, which is taken orally, takes place in a clinic under medical supervision. Mifepristone, also known as RU-486, blocks the hormone progesterone, which is essential to the buildup of the uterine lining that will support the embryo in the womb. The dose of this drug causes the lining to break down, and bleeding similar to a menstrual period occurs.


About three or four days later, once the lining is weakened, misoprostol is administered. Some doctors require that patients return to the clinic for the misoprostol dose, while others allow women to take misoprostol in their own homes. The FDA approved oral use of misoprostol, though some women have been advised to administer the dose as a vaginal suppository. The vaginal method has been linked with several deaths because the delivery method suppresses some of the body's natural immune responses [source: University of Michigan]. Misoprostol causes uterine contractions to begin, and the contents of the uterus are expelled in a process very similar to that of miscarriage. Bleeding can last up to two weeks.

Because a medical abortion ends much like a miscarriage, the possible side effects are very similar; the woman may experience nausea, vomiting or diarrhea. There are more serious complications. Excessive bleeding can occur if a uterine muscle ruptures, or the cervix could become blocked if all of the tissue and blood is not expelled. However, medical abortions are effective 95 to 98 percent of the time when done in the first nine weeks of pregnancy [source: WebMD].

If the medical abortion fails, or if a woman is past the ninth week of pregnancy, then a surgical abortion will be performed. We'll cover that procedure on the next page.