The Tennessee House of Representatives passed a controversial bill Thursday that would ban abortions after a fetal heartbeat is detected, legislation that could become among the most restrictive in the nation.

Amid early confusion among Republicans about proposed amendments and criticism from Democrats, the 99-member House approved the measure on a 65-21 vote.

"Colleagues, we cannot continue to allow the slaughter of the unborn while we hope for better circumstances," bill sponsor Micah Van Huss, R-Jonesborough, said from the House floor.

Still, the legislation could face obstacles on its way to final adoption. The Senate, where it could face more scrutiny, has yet to take it up.

And Tennessee Right to Life has opposed the bill, maintaining that the organization is focused on advocating for abortion restrictions it believes can survive legal challenges.

Brian Harris, the organization's president, said after the bill's passage the group would continue to express its concerns about the measure.

The state attorney general in 2017 released an opinion calling the restriction "constitutionally suspect," prompting a similar bill that had been filed at the time to fail a week later.

Both the American Civil Liberties Union and Planned Parenthood of Tennessee and Northern Mississippi on Thursday said they plan to file a lawsuit if the bill becomes law.

But Republican overwhelmingly supported it, with a number of GOP House members speaking out in favor of the bill.

WHAT YOU NEED TO KNOW:Tennessee's fetal heartbeat bill

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GOP supporter: 'Inject comment sense into our code'

Rep. Matthew Hill, R-Jonesborough, called the legislation "long overdue," though he urged the body to adopt an amendment that would ensure the state's current 20-week abortion ban remains in place if a court strikes the new proposal down.

The House approved the amendment.

"It is not overly complicated," Hill said. "We have a responsibility as the representatives of our districts, of our citizens, to ensure that life, innocent life, is protected in all its stages. We will be able to inject some common sense into our code."

Rep. Esther Helton, R-East Ridge, spoke of her own decision as a high school senior at age 17 to give birth to her son, while Rep. Mary Littleton, R-Dickson, recalled hearing her first child's heartbeat 42 years ago.

Two Democrats, Rep. John DeBerry of Memphis and Rep. John Mark Windle of Livingston, were among the 65 members voting in favor of the legislation. Seven Republicans declined to vote.

Senate speaker says bill 'hasn't had a very good reception'

Lt. Gov. Randy McNally, R-Oak Ridge, told reporters Thursday he preferred the Senate delay taking up the measure until there’s some clarity about other similar proposed abortion laws in other states, which are facing legal action.

“So far, it hasn’t had a very good reception,” he said.

McNally said the Senate wants to make sure whatever is considered in the upper chamber would not lead to any successful legal challenge and result in giving money to pro-choice groups.

As far as timing, McNally said the Senate could make a decision on the bill toward the end of the legislative session.

“I’m hoping that we can find a way that doesn’t get us in court on a losing battle and does accomplish what the intent of (the bill) is to do,” he said.

He said he "would hate to see a court rule that the whole thing is unconstitutional and charge the state attorney’s fees.”

Democrat who filed rape, incest amendment prohibited from speaking

Among the amendments set to be considered Thursday was one from Rep. Gloria Johnson, D-Knoxville, that would allow abortions in the case of rape or incest.

With her hand raised, Johnson remained standing throughout the floor discussion in an attempt to present her amendment, though House Speaker Glen Casada, R-Franklin, ignored her, declining to call on Johnson as he allowed other Republicans and Democrats to speak.

Republicans voted to end discussion before she could speak, a move House Democratic Caucus Chair Mike Stewart of Nashville said afterward was a deliberate act by Casada to prevent Johnson's amendment from being heard.

Casada declined to say why he didn't allow Johnson to speak, explaining that he was "more than generous" in calling on Democrats during the debate and that it was out of his hands once a motion was called to end discussion.

Democratic leader: Bill 'lacks compassion'

House Majority Leader Karen Camper, D-Memphis, said the legislation "lacks compassion" for those in cases of rape and incest.

"From a compassionate perspective, to not include those protections is unimaginable to me, Mr. Speaker," she said.

Members around the room responded with jeers as Rep. London Lamar, D-Memphis, suggested others in the chamber weren't of childbearing age, as she was.

"I think I'm one of the only woman in this house who can still have children," Lamar said. "No woman, including myself, should have to carry a rapist’s baby."

Rep. Bill Dunn, R-Knoxville, who had concerns about the legal implications of the bill, said he considered some of the amendments significant enough to potentially require the House to send the legislation back to the health committee. That ultimately did not take place.

"My concern with the bill as drafted is, No. 1, it will probably never save a life if we go by what's happened in the past," Dunn said.

"If it's challenged in the courts, it's going to drive up a legal bill, so our money is going to be going to pro-abortion groups."

Confusion, debate, arises during morning caucus meeting

During a morning GOP caucus meeting, lawmakers discussed several of the recently filed amendments that would change the legislation.

Rep. Kevin Vaughan, R-Collierville, said there was "broad support" for Van Huss' legislation in the caucus, but given the various amendments, it could create confusion.

"When we get on the floor today, this is going to be one of the most publicized votes that we as a caucus carry this year," he said.

"For us to be out there looking at each other with a blank look on our face and then trying to figure out which (amendments) are good and which ones are bad, I think will put all of us to where we look less than professional and look like we don't really have our act together."

Vaughan said if Republicans were confused about the legislation, it would "weaken" the party's moral high ground.

In general, Van Huss said he did not consider the amendments, which were mostly from Republicans, hostile to the bill and he would follow the desires of the caucus.

"I'm happy with the bill as written, but I do believe that a couple of these amendments would actually support (the legislation)," he said.

Dunn said without his amendment, the bill could "potentially destroy all of the pro-life legislation we have." He quickly corrected himself and said "not all."

Van Huss defended the bill again and said he received reassurances from attorneys his bill was in good standing.

BILL HAS OPPONENTS:Tennessee Catholic bishops oppose 'heartbeat' abortion restriction, citing legal worries

Protesters gather outside House chamber ahead of abortion vote

Several protesters of the legislation had shown up at the Capitol prior to the start of the House's 9 a.m. floor session.

As members entered the chamber, dozens of chanting protesters held signs describing various dangerous ways a woman could induce an abortion on her own, such as with a "coat hanger" or "throwing yourself down the stairs."

Hill engaged with one of the women protesting, who asked him why he wouldn't support legislation allowing for an abortion in the case of rape.

"I want all innocent life to have a chance," he said.

"And she's not innocent when she was raped?" the woman replied.

Anita Wadhwani contributed to this report.

TENNESSEE DEMOCRATS:Conflicted on abortion, one House leader is crossing the state to talk about it

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Reach Joel Ebert at jebert@tennessean.com or 615-772-1681 and on Twitter @joelebert29. Reach Natalie Allison at nallison@tennessean.com. Follow her on Twitter at @natalie_allison.