Rep. Bart Stupak argued Thursday that the provision in the Senate-passed version has language that would permit the federal government to "directly subsidize abortions."
The Michigan Democrat said he supports health care change, but he said several Democrats who voted for it the House would oppose it next time around in the absence of change. Stupak said on ABC's "Good Morning America" that "we're not going to bypass some principles that we believe strongly about." The administration argues that Mr. Obama's bill would retain existing restrictions on federally-financed abortions.
In a speech Wednesday at the White House, Mr. Obama called on lawmakers to end a year of legislative struggle and angry public debate and enact legislation ushering in near-universal health coverage for the first time in the country's history. He called for an "up-or-down vote" within weeks under rules denying Republicans the ability to block the bill with a filibuster.
"At stake right now is not just our ability to solve this problem, but our ability to solve any problem," the president said. "And so I ask Congress to finish its work, and I look forward to signing this reform into law."
The president will begin campaigning for health care legislation next week with stops in Philadelphia and St. Louis, reports CBS News senior White House correspondent Bill Plante.
Appearing before a select audience, many of them wearing white medical coats, Mr. Obama firmly rejected calls from Republicans to draft new legislation from scratch.
"I don't see how another year of negotiations would help," he said. "I believe the United States Congress owes the American people a final vote."
Mr. Obama's endorsement of an up-or-down vote sealed Democrats' intention to move forward under rules allowing for a simple majority vote in the Senate, thereby circumventing Republicans, who now command enough votes to deny Democrats the 60-vote supermajority normally needed to act.
At its core, the legislation still is largely along the lines Mr. Obama has long sought. It would extend coverage to tens of millions of uninsured Americans while cracking down on insurance company practices such as denying policies on the basis of pre-existing medical conditions. An insurance exchange would be created in which private companies could sell policies to consumers.
Much of the cost of the legislation, nearly $1 trillion over a decade, would be financed by cuts in future Medicare payments and higher payroll taxes on individuals earning more than $200,000 and couples more than $250,000.
In his latest changes Mr. Obama added some Republican ideas raised at last week's bipartisan summit, including renewed efforts on changes in medical malpractice and rooting out waste and fraud from the system.