WASHINGTON (AP) -- The abortion pill RU-486 is safe enough to remain on the market with strengthened warnings, the government said Tuesday despite a third death after the drug's use.

Critics said scrutiny of the drug would only increase. "I think you'll see the opposition, but not just from people who are pro-life," said Wendy Wright, senior policy director at Concerned Women for America. "This is a dangerous drug."

An abortion rights advocate hoped the expanded black box warning would not discourage women.

"It is my hope that women will not be afraid" to use mifepristone, originally known as RU-486, to induce abortion, said Vanessa Cullins, vice president for medical affairs at Planned Parenthood Federation of America. "All of us need to understand that no procedure, no medication is risk-free."

The federation uses the abortion pill at 222 of its 845 clinics.

The Food and Drug Administration said its decision to bolster safety warnings was triggered by a third death after RU-486 use.

"There was absolutely no political pressure," Dr. Steven Galson, acting director of the FDA's Center for Drug Evaluation and Research, said when asked if the Bush administration had weighed in. "This was a science-based decision."

At least three women who took the pill in the United States have died, although the FDA says it has not definitively tied any death to use of the pill.

Those three deaths were among 676 adverse events reported through Nov. 5 by women who used the abortion pill. The problems included sickness and dizziness as well as more serious illnesses that required hospitalization, according to the FDA.

Seventeen women used RU-486 even though they had tubal pregnancies; the drug is not to be used by women with suspected or confirmed ectopic pregnancies, in which the fertilized egg has implanted outside the uterus.

Another 72 women bled so heavily after using the abortion pill that they required blood transfusions. Seven women suffered serious bacterial infections, including sepsis.

"We are concerned about any drug that is related to serious medical complications and, certainly, death," Galson told reporters.

Still, infection, bleeding and death can accompany abortion, whether accomplished by surgery or medication. The same events can happen during childbirth.

"We feel that the safety profile of this drug, along with the steps that we're taking ... are adequate to allow the drug to be used safely," Galson said.

An attorney who represented the estate of a Tennessee woman who died in 2001 said the agency could do more. The FDA could prohibit RU-486 use until doctors rule out tubal pregnancies, difficult to detect in the first five weeks, said the attorney, Hoyt Samples.

Brenda Vise, a 38-year-old former nurse, died in the hospital where she once worked after a ruptured tubal pregnancy. In eight to 10 calls over two days to the clinic that gave her RU-486, she was told the severe pain and cramps she felt were normal.

"The real problem is the use of this drug masks symptoms of ectopic pregnancies," Samples said.

The FDA approved Mifeprex - Danco Laboratories' trademark for mifepristone - in 2000 to terminate pregnancy up to 49 days after the beginning of the last menstrual cycle. The drug blocks progesterone, a hormone required to sustain a pregnancy. When followed by another medicine, misoprostol, Mifeprex terminates the pregnancy.

Mifeprex already carries a black box warning, the agency's most strident alert, to highlight other safety concerns. The FDA said Monday it was expanding the drug's black box warning.

Serious bacterial infection may happen silently, without typical signs of infection like fever or tenderness, the label warns. Doctors should remain alert to the possibility a patient has undiagnosed tubal pregnancy, since symptoms are similar, the label says.

Women who take the pill must sign a patient agreement pledging to contact a doctor immediately if they have fever higher than 100.4 degrees that lasts more than four hours or severe abdominal pain. The women are also warned that heavy bleeding - enough to soak two thick, full-sized sanitary pads per hour for two consecutive hours - is reason to contact a doctor.

According to Danco, 360,000 American women have used the pill since it was approved by the FDA.

"The drug is safe. It's effective. And it provides another option for women to end early pregnancy," said Danco spokeswoman Cynthia Summers.

Monty Patterson, father of a teenager who died after taking RU-486, says the government's new safety warnings aren't enough.

Patterson's 18-year-old daughter, Holly, died Sept. 17, 2003, of septic shock caused by inflammation of the uterus. The teen took RU-486 on Sept. 10 to terminate an unplanned pregnancy, Patterson said.

Now that three women have died, he said, the FDA should bar sales of the abortion pill.

"How many more deaths is it going to take before the FDA takes action to remove this drug from the market?" said Patterson, 51, of Livermore, Calif.

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