Holly Patterson, who lived in the San Francisco suburb of Livermore, visited a Planned Parenthood clinic Sept. 10 to take the pill. She followed the prescribed procedure for using RU-486, taking two more pills at home in the following days.
After experiencing bleeding and cramps so severe that she was unable to walk, her boyfriend rushed her to the hospital, where she was given painkillers and sent home. She was back in the hospital a few days later and died on Sept. 17.
An autopsy has been scheduled to determine the cause of death. But her father, Monty Patterson, said he learned from an attending physician at the hospital that she had died after a massive infection caused by fragments of the fetus left inside her uterus caused her to go into septic shock. He said he had no idea that his daughter was pregnant or that she was taking abortion drugs.
"Holly was very much in trouble, and the doctor had mentioned that she had taken an abortion pill which shocked me and surprised me at the time, because I had no idea that that's what her problem was," Patterson told CBS News' The Early Show co-anchor Rene Syler on Monday.
Planned Parenthood also said it is investigating Patterson's death.
A spokeswoman for Danco Laboratories, which makes RU-486, estimated that 200,000 women in the United States and more than 1 million worldwide have used the pill since it was invented in France in the 1980s.
Two women who took it in the United States have died, although the FDA says it is unclear if their deaths were directly related to the pill's use.
Patients who take RU-486 take the first pill under the care of a physician. A second medication called misoprostol, taken three days later, induces labor so the embryo can be expelled. In 5 to 8 percent of cases, surgery is required to stop the patient's bleeding.
Planned Parenthood's web site compares the process to having a miscarriage.
Eric Schaff, chair of the National Abortion Federation, which promotes non-surgical abortion rights, said aspirin causes more deaths than RU-486.
But anti-abortion rights groups such as the National Right to Life Committee insist that the pills "offer a whole new set of significant risks," and makes abortion seem too simple. A report on the group's Web site says the pill gives "supporters of abortion a chance to change the image of abortion, making it seem as simple as taking a pill."
According to national mortality tables, 37 women died in 2000 from pregnancies with abortive outcomes. A total of 404 women died in pregancies overall. In 1999, the Centers for Disease Control and Prevention recorded 861,789 abortions.