Mr Obama wants to provide health insurance to those who do not have it
President Barack Obama has stepped up his efforts to gain support for his embattled healthcare reform plans by giving an interview to US Fox News.
The broadcaster has been criticised by the White House for its perceived right-wing bias.
Facing tough questioning, Mr Obama voiced confidence that the reform bill would finally be passed by Congress.
Mr Obama has received a boost from Congressman Dennis Kucinich, who says he will now support the legislation.
Several Catholic religious orders said they were now satisfied the legislation would not allow public money to be used for abortions and so voiced their backing.
With just days to go before this protracted battle over healthcare reaches its climax in Congress, and with the outcome still too close to call, President Obama is campaigning hard, the BBC's Paul Adams in Washington says.
He has been on the road, with his shirtsleeves rolled up, making passionate speeches, and now he has taken the offensive to Fox News, regarded by this White House as fundamentally opposed to "the president and all his works", our correspondent says.
The interview, with combative presenter Bret Baier, was largely unproductive. The president wanted to extol the virtues of the reform bill, while Mr Baier wanted to grill him about some of the complex - and controversial - congressional procedures being explored by the Democrats as they try to get the bill passed.
President Obama chided the interviewer, Bret Baier, for interrupting his answers.
"Bret, you've got to let me finish my answers," he said.
"Sir, I know you don't like to filibuster, but..."Mr Baier said.
"Well, I'm trying to answer your question and you keep on interrupting," the president replied.
Mr Obama did receive some good news on Wednesday, our correspondent says.
One of the bill's fierce Democratic critics, Mr Kucinich, who had previously voted against the legislation, announced that he intended to support it.
"I know I have to make a decision, not on the bill as I would like to see it but as it is," he said.
"You do have to be very careful that the potential of President Obama's presidency not be destroyed by this debate. Even though I have many differences with him on policy, there's something much bigger at stake here for America."
And a number of Catholic religious orders, representing 59,000 nuns, said they were now satisfied the bill does not allow taxpayer dollars to be used to fund abortions.
This could help to win over a handful of Conservative Democrats, our correspondent adds.
Republicans are opposed to the proposed reforms, arguing that they will give the government too much control over healthcare and be mainly paid for by higher taxes and cuts in Medicare, the government-run health scheme for Americans aged 65 or over.