Ohio legislators passed a "heartbeat bill" Wednesday that bans abortion after a fetus's heartbeat can be heard — on average around six weeks into a pregnancy. The bill has no exception for cases of rape or incest.

The bill was tacked on at the last minute to another bill addressing child abuse. It was approved in the Republican-dominated state House and Senate, and will now move on to Republican and anti-abortion Gov. John Kasich's desk. He will sign or veto it within the next 10 days.

“A hallmark of lame duck" — a term used to describe sessions of lawmakers that sit between when elections are over and the new lawmakers take office — "is a flood of bills, including bills inside of bills, and we will closely examine everything we receive," said Kasich's press secretary, Emmalee Kalmbach.

The American Civil Liberties Union told BuzzFeed News that they are preparing to fight back against ban, should it become law. "if Governor Kasich signs that bill, we will absolutely challenge that in federal court," Mike Brickner, senior policy director of ACLU Ohio, said. "We believe that it is unconstitutional."

Many women do not know they are pregnant until they have missed two periods, which can often be around eight weeks. Others may find out before the six-week mark, but might still be unable to get an abortion in time because there are a lack of clinics in Ohio and state laws require women wait 24 hours between an informational appointment about abortion and having the procedure done.

Dr. Diane Horvath-Cosper, a practitioner of clinical medicine and member of Physicians for Reproductive Health, told BuzzFeed News that the bill was "extreme" and "dangerous."

"We have evidence that shows that banning abortion does not make it go away — it just increases the chances that people will seek care in potentially unsafe environments," Horvath-Cosper said.

The ban was attached at the last minute to another measure, House Bill 493, which expedites the process by which doctors report cases of child abuse to law enforcement authorities.

The bill was written by anti-abortion and anti-LGBT rights activist Janet Porter (formerly Janet Folger). She authored the book The Criminalization of Christianity: Read This Book Before It Becomes Illegal!

Republican state Sen. Kris Jordan called for the "heartbeat" amendment to be included earlier Wednesday morning. The Ohio Senate voted 20–11 to add the amendment, then passed the bill with a primarily partisan 21–10 vote.

"We are a pro-life caucus," Jordan wrote in a statement. "The passage of this legislation in the Ohio Senate demonstrates our commitment to protecting the children of Ohio at every stage of life."

Ohio Sen. Sherrod Brown, a Democrat, told BuzzFeed News Wednesday that he believed the bill had "been shown to be unconstitutional."

“It’d be nice if the legislature would actually be doing something about jobs and doing something about renewable energy standards and keeping the economy growth going that way instead of passing unconstitutional bills,” the senator said, going on to list pieces of legislation he believed Ohio's lawmakers should be working on instead.

Following Trump's election, anti-abortion legislation has been introduced all over the country — including a law that would ban abortion entirely in Indiana. Pro–abortion rights groups are fighting back.

"Politicians resorted to underhanded tactics to try and sneak through this harmful legislation without notice," Dawn Laguens, executive vice president of Planned Parenthood Action Fund told BuzzFeed News. She said she expects Ohio citizens to protest the bill adding, "we will fight back, no matter what."

Last week, Planned Parenthood, the Center for Reproductive Rights, and the ACLU filed lawsuits in three states to overturn abortion restrictions, saying that they were against the 1973 Supreme Court decision Roe v. Wade, as well as June's decision upholding the abortion rights law. In the latter, the court, by a vote of 5–3, struck down abortion provider restrictions in Texas.

If abortion legislation is challenged and makes its way to the US Supreme Court, it would face the question of whether it places an undue burden on a woman’s right to an abortion.

If Kasich signs the bill or does nothing, the bill will become law early next year.