COLUMBUS – Ohio lawmakers pushed back a Thursday vote on the “heartbeat bill," raising doubt the GOP-controlled legislature will have enough time to pass the controversial legislation and override an expected veto by Republican Gov. John Kasich.

The bill, House Bill 258, would ban abortions once a fetal heartbeat is detected, as early as six weeks into a woman’s pregnancy and before many women know they are pregnant. Similar abortion bans have been found unconstitutional in other states.

Sen. Dave Burke, R-Marysville, said senators want to amend the bill but those changes haven't been discussed yet.

"We believe it is in the public's best interest to allow those to mature," Burke said.

Supporters of the bill were eyeing a Thursday floor vote in the Senate to allow enough time for Kasich to consider the bill – he has 10 days except Sundays – and for a veto override vote on Dec. 19.

But Thursday's delay puts that plan in limbo.

If the Senate passes the bill next week, Kasich could wait until the days leading up to Christmas to veto the bill. Legislators would have to come back to Columbus after the holiday and before the end of the year to vote.

And it's not known whether either chamber has the minimum number of votes – 60 in the House and 20 in the Senate – to make the bill law. Exactly 60 lawmakers in the House voted for the bill, so all would need to show up to vote and vote the same way.

Meanwhile, a bill that would ban most abortions after 12 weeks could quickly move to Kasich's desk next week.

Burke said the heartbeat bill is expected to clear a committee vote next week, but he wouldn't discuss the bill's future beyond that point. Anti-abortion activist Janet Porter, who has pushed for the heartbeat bill for several years, declined to comment on the delay.

What would the heartbeat bill do?

The bill would ban abortions once a fetal heartbeat can be detected, which is defined as "cardiac activity or the steady and repetitive rhythmic contraction of the fetal heart." Physicians who perform abortions would face fifth-degree felony charges, punishable by up to one year in prison.

The bill makes no exception for cases of rape or incest, but does allow abortions to prevent the woman's death or "substantial and irreversible impairment of a major bodily function."

Is it constitutional?

The 1973 landmark Roe v. Wade decision established women’s right to privacy extends to her decision to seek an abortion before the fetus is viable. Courts have allowed states to pass abortion restrictions so long as they don’t impose an undue burden.

Heartbeat bills have passed in Arkansas, North Dakota and Iowa, but courts have blocked them all from going into effect. The Supreme Court has declined to weigh in.

Donald Trump’s election to the presidency – and his power to choose conservative U.S. Supreme Court justices – emboldened Ohio Republicans to send the heartbeat language to Kasich in 2016. Their hope: set up a direct challenge to Roe v. Wade with a more conservative court.

Kasich vetoed the measure, citing its unconstitutionality. But he signed legislation banning abortions 20 weeks after conception, or about 22 weeks gestation, which is how medical professionals measure pregnancy.

Governor-elect Mike DeWine said he would sign a heartbeat bill if it came across his desk.

What happens next?

Abortion rights supporters said Thursday's delay was a "good sign" that the legislature won't rush the bill. But Jaime Miracle, deputy director of NARAL Pro-Choice Ohio, said they're still watching the heartbeat bill and a handful of others that would restrict access to abortion.

One of those is Senate Bill 145, which would ban dilation and evacuation. The procedure is the most commonly used for abortions after 12 weeks gestation and before Ohio's limit of roughly 22 weeks. The bill is backed by Ohio Right to Life, the state's largest anti-abortion organization.

The bill cleared the Senate earlier this year and could move out of the House before the end of the year, during this "lame duck" session. Any bills that don't pass both chambers by Dec. 31 will die and have to start over in the next two-year legislative session.

"While we celebrate a temporary stall we will stay vigilant through the rest of lame duck and Mike DeWine's governorship that starts in January to make sure we protect abortion access in the state of Ohio," Miracle said.