COLUMBUS (Reuters) - The Ohio Senate on Wednesday suspended discussion of a controversial bill that would have banned abortions after the first fetal heartbeat was detected.

The measure, known as House Bill 125, has already passed the Ohio House. If it became law, it would be the toughest restriction on abortions in the nation.

The American Civil Liberties Union said on December 6 it would sue if Ohio state lawmakers pass either that bill or another that would not allow Ohioans to buy coverage for abortion from new healthcare exchanges set up as part of the federal health care reform plan. Both, ACLU said, are unconstitutional.

Fear of expensive legal battles over the law may have prompted a wave of amendments by Senate backers to the bill. But the wording of the bill has split anti-abortion backers.

"Supporters of the bill delivered more than 20 amendments on Wednesday, asking us to make changes after months of deliberation in both the House and Senate," Ohio Senate President Tom Niehaus, a Republican, said in a statement.

"These eleventh hour revisions only serve to create more uncertainty about a very contentious issue. We've now heard hours of testimony that indicate a sharp disagreement within the pro-life community over the direction of this bill, and I believe our members need additional time to weigh the arguments. Therefore, I have asked the committee chairman to suspend hearings on the bill," Niehaus said.

"Our majority caucus is staunchly pro-life, and we will take every responsible step to advance the protection of unborn children," he added. "But we cannot move forward on a bill that has so far created more confusion than consensus."

Ohio Right to Life has not backed the heartbeat bill because they say the current makeup of the U.S. Supreme Court is not favorable to abortion opponents. This stand has caused divisions within the state's anti-abortion community.

Stephanie Krider, legislative affairs director at Ohio Right to Life, had testified to a state senate committee that the Court might actually use the heartbeat law to reaffirm Roe v. Wade and eliminate other restrictions on abortion.

"Let's not let emotion blind us from reality and let's make sure that we do not, unintentionally, do more harm than good," Krider said.

(Reporting by Jo Ingles. Editing by Peter Bohan)