After a storm of protests from abortion rights groups, the American health secretary, Michael Leavitt, has for the time being backed down from issuing a legally binding regulation that would have made contraception more difficult to obtain by redefining birth control pills, the "morning-after pill" and devices such as IUDs as forms of abortion.

Health workers already have the right, guaranteed by federal law, to decline to take part in abortions on the grounds of conscience. The proposed change in definition would have allowed them to legally deny contraception to patients as well.

"An early draft of the regulations found its way into public circulation before it had reached my review," Leavitt wrote in his blog on 11 August. "It contained words that lead some to conclude my intent is to deal with the subject of contraceptives, somehow defining them as abortion. Not true."

Leavitt's denial is the latest twist in what is believed by abortion rights and women's groups to be a last-gasp attempt by the Bush administration to accommodate the wishes of its conservative Christian supporters before the president hands over the White House to his successor in January.

Bush's appointment of conservatives to the Supreme Court has already led to a judgment outlawing most late-term abortions. It is the most significant restriction to date of the right of American women to obtain abortions, established by the 1973 landmark ruling Roe v Wade.

Despite his pronouncement, Leavitt is leaving the door open to issuing a regulation "directly focused on the protection of practitioner conscience". Many, including Hillary Clinton, believe this will be a back-door way of making it more difficult for Americans to obtain contraceptives. Clinton has demanded an urgent meeting with Leavitt to clarify his intentions.

Earlier this year, Leavitt responded to a letter sent by the American Board of Obstetrics and Gynaecology and the American College of Obstetricians and Gynaecologists. The circular demanded that members who object to assisting in abortions refer patients "in a timely manner" to practitioners who do not have moral objections to terminating a pregnancy, or they would face expulsion.

Leavitt suggested that the bodies rethink their action, which could deny the legal right of anti-abortion medical practitioners to exercise their conscience, by making them assist in abortions through the act of referral. "In particular," he wrote, "I am concerned that such actions by these entities would violate federal laws against discrimination."

The two institutions did not budge. As Leavitt put it in his recent blog: "Frankly, I found their response to be dodgy and unsatisfying."

In response, Leavitt's officials issued a press release declaring: "Unless changes are made, physicians could be forced to refer patients for abortions even if it violates their conscience." The release argued that, by passing patients on to others who would facilitate an abortion, the dissenting practitioners would still be in conflict with their conscience.

The health department then drafted a regulation to halt federal funding to any medical institution that requires health-care workers to take part in abortions, defined as "any of the various procedures - including the prescription, dispensing and administration of any drug or the performance of any procedure or any other action - that results in the termination of the life of a human being in utero between conception and natural birth, whether before or after implantation".

Reaction to the draft regulation, which would have the full force of law and would not need to be endorsed by the president or ratified by Congress, was swift. Planned Parenthood and 56 other abortion rights groups and contraceptive drug companies wrote to Leavitt demanding that he think again.

They argued that hospitals and clinics would be powerless to prevent their employees from failing to issue contraceptives and that the "rule permits health-care providers to refuse to perform any service they deem morally objectionable, which raises critical questions about access to all health-care services".

Cecile Richards, president of the Planned Parenthood Federation of America, declared: "This administration needs to stop playing word games with women's health, and state clearly whether they will reject any regulations that will undermine women's access to basic health care."

The argument over medical practitioners' rights shadows a similar battle over contraception among pharmacists, who are given similar conscience rights that allow them to deny patients contraceptives if they have moral objections to birth control.

In large towns and cities, this is little more than an inconvenience, but in rural areas and in parts of cities ill-served by pharmacists, the denial of contraception amounts to a restriction on a person's right to avoid pregnancy or practise safe sex.

Anti-abortion groups have joined the debate, hoping that publicity surrounding the arguments will prompt political pressure from Christian groups and cause Leavitt to make contraception more difficult to obtain.

As Jen Catelli, of the anti-abortion American Life League, put it: "If he is seeking to protect conscience rights of those who want nothing to do with abortion, he needs to recognise that contraceptives can cause abortions. The truth is that life begins at creation, and anything that destroys that life is an abortion."