RU-486 was approved Thursday by the Food and Drug Administration, ending a battle that has involved two presidents, several countries and heated debate for 12 years.
Approval of the drug gives American women a pharmaceutical abortion method already in wide use in France, Britain, China and 10 other countries.
But since the FDA action took place in the closing weeks of a national political campaign, it drew quick and heated comments from both sides of the issue.
Texas Gov. George W. Bush, the Republican presidential nominee, called the FDA decision "wrong" and said he feared that the availability of RU-486 "will make abortions more and more common."
Health experts, however, said abortions did not increase after the drug was introduced in Europe.
A Bush campaign spokesman said a president cannot order drugs off the market, but, if elected, Bush would appoint an FDA commissioner "to make sure the FDA considered the risk and did not take this action as a result of political pressure from the White House."
Vice President Al Gore, Bush's Democratic opponent, supported approval of the abortion pill, saying the decision was "not about politics, but the health and safety of American women and a woman's fundamental right to choose."
RU-486 was developed in France and became available there in 1988. In 1989, Bush's father, President George Bush, ordered the FDA to ban importation of the drug for personal use. In 1993, President Clinton ordered a re-evaluation of the ban and sought ways to provide RU-486 for U.S. researchers after its French manufacturer refused to supply it.
Abortion opponent Rep. Chris Smith, R-N.J., called the abortion pill "baby poison," adding that "RU-486 is not just poison for babies, it is potential poison for the mothers who take it." He said it can cause prolonged bleeding and severe cramps.
Rep. Tom Coburn, R-Okla., promised legislation calling for severe limits on which doctors could administer the abortion pill.
On the other side, Sen. Barbara Boxer, D-Calif., said the drug provides an abortion method "that avoids invasive surgery."
"Today is a day that women should remember because their health and their choices are finally being respected," she said.
The pill, known chemically as mifepristone and by the brand name Mifeprex, will be available to doctors within a month.
Mifepristone blocks a hormone vital to sustaining pregnancy and works only during the first seven weeks of pregnancy, when an embryo is about one-fifth of an inch.
Two days after taking mifepristone, women take a second drug that causes cramping and bleeding as the embryo is expelled, much like a miscarriage.
"For those who choose to have an early termination of their pregnancy, this is a reasonable medical alternative," said FDA Commissioner Jane Henney. She approved mifepristone based on studies that found it 92 percent to 95 percent effective in causing abortion.
Researchers say complications are rare, with serious bleeding in 1 percent of women. The pharmaceutical abortion does require three doctor visits and the FDA restricted prescribing RU-486 to doctors with certain training. The agency required that detailed patient-information brochures be given to every woman.
But Smith claimed in a statement that a French study showed that out of 950 women who used the drug, 270 required narcotics to control intense pain and seven required blood transfusions.
Richard Hausknecht, medical director of Danco Laboratories, marketer of mifepristone, called it "a very, very safe drug."
"At long last, science trumps anti-abortion politics and medical McCarthyism," said Eleanor Smeal of the Feminist Majority Foundation.
Mifepristone may "turn the tide against anti-choice intimidation," because doctors not offering surgical abortion can use the pill in private offices instead of protester-targeted clinics, added Planned Parenthood president Gloria Feldt.
A Kaiser Family Foundation survey of 767 physicians found that a third of doctors who don't now provide surgical abortions would consider prescribing RU-486.
But anti-abortion groups pledged to continue their opposition, with Judie Brown of the American Life League saying: "We will not tolerate the FDA's decision to approve the destruction of innocent human persons through chemical abortion."
The pill's journey to the United States began in 1995, when French manufacturer Roussel-Uclaf turned over U.S. rights to the drug to the nonprofit Population Council of New York. The council began clinical trials needed for FDA approval and created Danco Laboratories to market mifepristone.
The FDA in 1996 declared mifepristone a safe and effective early abortion method, but delayed full approval because Danco had problems satisfying manufacturing and other final requirements.
President Clinton said the FDA's four-year investigation shows the decision was "purely one of science and medicine." He said the FDA "bent over backward to do a lot of serious inquiries."
On the Net:
National Abortion Federation: http://www.earlyoptions.org
National Right to Life Committee: http://www.nrlc.org