By a vote of 54-45, senators dismissed the abortion amendment offered by Democratic Sen. Ben Nelson of Nebraska and Sen. Orrin Hatch, R-Utah.
Nelson had threatened to vote against final passage if his amendment were not included. But he declined to say after his amendment was defeated if he would abandon the Democrats' razor thin 60-vote majority.
"This makes it very hard for me to support it," Nelson told reporters after the vote.
Nelson told reporters he is not actively involved in negotiations with Reid to find middle ground on the abortion issue.
"I have no plan B and I'm not looking for a plan B," he said. "This was decided. It's there."
Democrats need 60 votes to avoid a Republican filibuster of their bill.
In casting his "No" vote, Reid acknowledged that while he might oppose abortion rights, it "doesn't mean I'm opposed to finding common ground for the greater good."