A French drug company is hoping to offer American women something their European counterparts already have: a pill that works long after 'the morning after.' The drug, dubbed ella, would be sold as a contraceptive _ one that could prevent pregnancy for as many as five days following unprotected sex. But the new drug is a close chemical relative of the abortion pill RU-486, raising the possibility that it could theoretically be used to induce abortion by making the womb inhospitable for an embryo. The controversy sparked by that ambiguity will force a panel of federal advisers scheduled to consider endorsing the drug next week to grapple with a host of thorny issues. The last time the Food and Drug Administration (FDA) vetted an emergency contraceptive _ Plan B, the so-called morning-after pill _ the decision was mired in debate over such fundamental questions as when life begins and the distinction between preventing and terminating a pregnancy. Ella is raising many of those same politically charged questions _ but more sharply, testing the Obama administration's pledge to keep ideology from influencing scientific decisions. Plan B, which works for up to 72 hours after unprotected sex, was eventually approved for sale without a prescription, though a doctor's order is required for girls younger than 17. The new drug promises to extend that period to at least 120 hours. Approved in Europe last year, ella is now available as an emergency contraceptive in at least 22 countries. Ella is being welcomed by many U.S. advocates for family planning and reproductive rights. Opponents of the new drug, however, argue that the French company and the FDA would be misleading the public by labeling ella as an emergency contraceptive. Its chemical similarity to RU-486 makes it more like the controversial abortion pill, which can terminate a pregnancy at up to nine weeks, they say. RU-486 has soared in popularity since approval 10 years ago in the United States, raising the possibility that ella _ or ulipristal acetate _ might become ubiquitous in American women's medicine cabinets. 'With ulipristal, women will be enticed to buy a poorly tested abortion drug, unaware of its medical risks, under the guise that it's a morning-after pill,' said Wendy Wright, of Concerned Women for America, which led the battle against Plan B. Plan B prevents a pregnancy by administering high doses of a hormone that mimics progesterone. It works primarily by inhibiting the ovaries from producing eggs. Critics argue it can also prevent a fertilized egg from implanting in the womb, which some consider equivalent to an abortion, making it a continuing focus of controversy. RU-486 works by blocking progesterone's activity. Because progesterone is needed to prepare the womb to accept a fertilized egg and to nurture a developing embryo, RU-486 can prevent a fertilized egg from implanting and dislodge growing embryos. Its chemical similarity raises the possibility that ella _ perhaps if taken at elevated doses _ may do the same thing, though no one knows for sure because the drug has never been tested that way. Opponents of the drug are convinced it will. 'It kills embryos, just like the abortion pill,' said Donna Harrison, president of the American Association of Pro-Life Obstetricians and Gynecologists. 'It's embryotoxic.' Critics fear that women who do not realize they are already pregnant will use the drug, unwittingly giving themselves an abortion. 'Women have a right to know this drug is destroying a life growing in their womb,' said Jeanne Monahan, director of the Family Research Council's Center for Human Dignity. 'The difference between preventing life and destroying life is hugely significant to many women. Women deserve to know that difference.' They also fear some women will purposefully try to use ella to abort a fetus, putting themselves at risk for potentially life-threatening complications that have been reported among a small number of women using RU-486 and possibly damage their developing child if it doesn't work. 'This not good for women's health or for their babies,' Monahan said. But proponents dismiss those concerns, saying ella has been tested only within five days of unprotected sex and there is no evidence that it works as anything other than a contraceptive. Ella appears to be about twice as effective as Plan B at preventing pregnancy, and its effectiveness does remains constant for at least 120 hours. Plan B, in contrast, begins to lose its effectiveness almost immediately and becomes ineffective after 72 hours. 'There is an great unmet need out there for emergency contraception that is effective as this for so long,' said Erin Gainer, chief executive of HRA Pharma of Paris. Studies involving more than 4,500 women in the United States and Europe show the ella is highly safe, producing only headaches, nausea, fatigue and other minor side effects, she said. The company has no plans to test ella as an abortion drug, but it did not appear to cause any problems for the handful of women who have become pregnant after taking the drug, she said. 'We're very clear on the fact that this is indeed a contraceptive _ a method of prevention of pregnancy,' Gainer said. But based on the FDA's repeated delays in approving the sale of Plan B without a prescription, Gainer and others said they feared the accusations might influence the agency. 'FDA should be a `Just the facts ma'am' organization,' said Susan F. Wood, an associate professor of the George Washington University School of Public Health and Health Services who resigned from the FDA to protest delays making Plan B more accessible. 'I'm hoping the FDA will take that position.' 'The people who are opposing this are not just opposed to abortion,' said Amy Allina, program director at the National Women's Health Network. 'They also opposed contraception and they are trying to confuse the issue.' If ella wins approval, it will likely inflame a long-running debate: whether doctors have an obligation to write prescriptions for medication they oppose on moral or religious grounds and whether pharmacists have an obligation to fill them. Many doctors and pharmacists already refuse to write or fill prescriptions for Plan B or refer patients elsewhere for it. 'Pharmacists will have more obvious reasons to refuse to dispense this drug, and to refuse to refer,' said Karen Brauer, president of the Pharmacists for Life International. 'My suspicion is that more pharmacists will wish to opt out of dispensing ulipristal than any other of the previous drugs.' 