U.S. District Judge James Whittemore did not immediately make a ruling after the two-hour hearing, and he gave no indication on when he might act on the request.
CBS News Legal Analyst Andrew Cohen said a ruling should be forthcoming sooner, rather than later.
"The judge made it clear that he understands the important time element here and I suspect he is balancing that pressure with the need to write a coherent order that takes into account a lot of very complicated and intertwining legal issues,'' said Cohen.
"The judge knows that whatever he decides is going to be immediately appealed up the ladder; that he won't be the last word on this. But he also knows that he will be the first voice from and for the federal judiciary to speak in the wake of the Congressional action over the weekend,'' said Cohen. "So there is an awful lot at stake for him as well."
The hearing came three days after the feeding tube was removed. Doctors have said Schiavo could survive one to two weeks without the tube.
During the hearing, David Gibbs, an attorney for the parents, said that forcing Terri Schiavo to die by starvation and dehydration would be "a mortal sin" under her Roman Catholic beliefs.
"It is a complete violation to her rights and to her religious liberty, to force her in a position of refusing nutrition," Gibbs told Whittemore.
But the judge told Gibbs that he still wasn't completely sold on the argument. "I think you'd be hard-pressed to convince me that you have a substantial likelihood" of the parents' lawsuit succeeding, the judge said.
George Felos, one of the attorneys for husband Michael Schiavo, told Whittemore that the case has been aired thoroughly in state courts and that forcing the 41-year-old severely brain damaged woman to endure another re-insertion of the tube would violate her civil rights.
"Every possible issue has been raised and re-raised, litigated and re-litigated," Felos said. "It's the elongation of these proceedings that have violated Mrs. Schiavo's due process rights."
The hearing followed of an extraordinary law granting the parents of the severely brain-damaged woman the right to ask a federal court to intervene in the case.
Overnight, the House, following a move by the Senate, passed a bill to let the parents ask a federal judge to prolong Schiavo's life by reinserting her feeding tube. Mr. Bush signed the measure less than an hour later.
The president, speaking in Arizona on Monday afternoon, said Congress had granted Schiavo's parents "another opportunity to save their daughter's life."
Mr. Bush said that in circumstances such as this, it's "wise to always err on the side of life."
Schiavo's husband, Michael Schiavo – who says it would be his wife's wish to die – said he was outraged that congressional leaders intervened in what he says is a private right-to-die decision.
"Those people that voted for this bill never asked for any information or any facts about this case," Schiavo said Monday morning on CBS News' The Early Show.
"This is a sad day for Terri, but what's worse is that it's a sad day for every person in the United States, that this Congress, this government, can walk right into your private lives and trample all over everything, and they have no remorse," Schiavo told co-anchor Harry Smith.
Mr. Bush was awakened to sign the bill shortly after it was approved by the House at 12:42 a.m. Monday and then rushed to him by staff secretary Brett Kavanaugh. The president stepped outside his bedroom and signed it at 1:11 a.m., standing in the hall of his private residence.
The White House said the legislation was narrowly tailored and not intended as a precedent for Congress to step into battles over the fate of seriously disabled or terminally ill patients.
"This is an extraordinary case," White House spokesman Scott McClellan said. "It is a complex case where serious questions and signficant doubts have been raised."
The bill passed the House after an often-wrenching debate that stretched past midnight. It won the backing of virtually all the Republicans and almost half the Democrats who sprinted back to the Capitol for the debate, while 174 of the House's 435 elected members did not vote.
"Tonight we have given Terri Schiavo all we could – a chance to live," said House Majority Leader Tom DeLay, R-Texas. "After four days of words, the best of them uttered in prayer, Congress has acted and a life may have been saved."
Many House Republicans said Schiavo isn't in the hopeless state that her husband portrays.
"We have heard very moving accounts of people close to Terri that she is, indeed, very much alive," said House Speaker Dennis Hastert, R-Ill. "She laughs, she cries and she smiles with those around her."
Some Democrats countered that elected lawmakers weren't qualified to make a medical diagnosis or second-guess the decisions made by Florida courts.
"I don't know who's right and who's wrong, but that's the point. Neither do my colleagues," said Rep. Jim Moran, D-Va.
A few Republicans questioned the motives of Schiavo's husband, Michael, suggesting he doesn't have his wife's best interest at heart.
"Now, he has had her feeding tube removed and sentenced her to a most excruciating death, citing Terri's own wishes as the rationale ..." said Rep. Jim Ryun, R-Kan. "Michael did not remember this supposed request until years after Terri's initial injuries when a cash settlement was awarded to her, a settlement he would stand to inherit."
And a few Democrats lobbed accusations at Republicans that political motives drove their passion for Schiavo and her parents.
"If you don't want a decision to be made politically, why in the world do you ask 535 politicians to make it? Does anyone think that this decision will be made without consideration of electoral support or party or ideology? Of course not," said Rep. Barney Frank, D-Mass.