Democrats in the House of Representatives scrambled on Wednesday to iron out lingering concerns over abortion in a healthcare reform bill that was headed to a close and potentially historic weekend debate.

House Democratic leaders planned a Saturday vote on the sweeping overhaul, which would launch the biggest changes to the U.S. healthcare system since the creation of the Medicare health program for the elderly in 1965.

We are on the verge of doing something great, House Speaker Nancy Pelosi, a Democrat, told reporters.

But with Republicans united in opposition, Democrats struggled to line up the 218 votes needed to pass the bill. It's going to be tight, a Democratic aide said.

Democratic leaders hoped to defuse a potential uprising by moderates within the party who want stronger language to ensure federal funds are not used to pay for abortions under the bill.

The overhaul, President Barack Obama's top domestic priority, is designed to rein in costs, expand coverage to millions of uninsured and bar insurance practices, such as denying coverage to people with pre-existing conditions.

The House bill would require individuals to buy insurance and all but the smallest employers to offer health coverage to workers. It also provide subsidies to help purchase insurance and would eliminate the industry's exemption from federal antitrust laws.

House Democratic leaders filed largely technical last-minute changes to the legislation late on Tuesday night, starting a 72-hour waiting period they had promised to Republicans and clearing the way for a Saturday vote.

House Rules Committee Chairwoman Louise Slaughter said she expected the rule-setting guidelines for the healthcare debate would incorporate anti-abortion language proposed by Representative Brad Ellsworth, a moderate Democrat.

His amendment would prohibit the use of federal funds to cover abortions and also guarantee access to insurance plans that would agree to refrain from covering abortion.

'UP IN THE AIR'

My goal is to ensure that federal taxpayer dollars are not going to abortions, but we aren't there yet, he told reporters. I think it's still pretty much up in the air.

Ellsworth's amendment has been attacked by some anti-abortion Democrats and the National Right to Life Committee, which called it a political fig leaf and urged Democrats to vote down any rule that included it.

The group prefers a proposal by Representative Bart Stupak, who leads about 40 moderate Democrats vowing to oppose the bill unless it is changed to their satisfaction on abortion.

Stupak wants to bar any federally subsidized insurance plan from paying for abortions, including government-run public plans created to compete with private insurers.

He and other abortion opponents argue federal subsidies under the bill would help pay for insurance plans that include abortion coverage, which means federal funds would be going toward abortions.

Ellsworth said three or four moderate Democrats had approached him to say his proposal would win their vote. That might be enough for Democrats, and every vote could be crucial when the House takes up the measure on Saturday.

Special election victories in California and New York gave Democrats two new members and two more likely yes votes on the healthcare bill, and leaders made plans to swear in the new members quickly so they could vote.

Democrats now hold a 258-177 majority in the House, where 218 votes are needed for passage. An unknown number of Democrats are expected to join Republicans in voting against the measure, leaving the final margin too close to call.

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