Lawmakers in Georgia and Tennessee have advanced bills that would ban most abortions when a fetal heartbeat is detected, usually around six weeks of pregnancy. Should they become law, both are expected to face legal challenges, as courts have historically ruled similar laws unconstitutional.

House Bill 481 passed the Georgia House by a vote of 93-73 last Thursday and now moves to the Senate, according to WSB-TV Atlanta. Governor Brian Kemp released a video message supporting the bill shortly after its passage.

The bill includes exceptions for pregnancies that are the result of rape or incest- which would be demonstrated by a police report filed by the woman- as well as when a pregnancy is deemed to threaten the life of the mother or to be "medically futile."

The Georgia Health and Human Services Committee tabled a second piece of legislation that would have created a "trigger law" to ban abortion if Roe v. Wade, the 1973 ruling that found a Constitutional right to abortion, is overturned by the Supreme Court.

Georgia House Democrats turned their back on Republican Rep. Ed Setzler as he introduced the heartbeat bill in the house chamber. Several Democrats had already walked out in protest of the bill.

In Tennessee, House Bill 77 passed the legislature 65-21 the same day and continues to the Senate. Gov. Bill Lee has said he will sign the heartbeat bill into law if it makes it to his desk.

Tennessee's Catholic bishops chose to oppose the state's heartbeat bill over concerns that it would not stand up to judicial scrutiny. Tennessee Right to Life, the state's leading pro-life group, also opposed the bill.

"While we wholeheartedly support the intention of the 'Heartbeat Bill' being considered by the Tennessee Legislature, we must also be prudent in how we combat the pro-abortion evil that dwells in our society," the bishops wrote in a Feb. 26 open letter.

The bishops cited similar laws in other states that were signed into law but never went into effect because of legal challenges. In those cases, the laws were found to be unconstitutional, and the state was forced to pay significant sums of money to the lawyers representing the pro-abortion challengers to the laws.

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Planned Parenthood, the nation's largest abortion chain, has already said they will file suit against Tennessee if the heartbeat bill becomes law. The American Civil Liberties Union has also vowed to challenge heartbeat bills in court in several states.

As an alternative, the bishops voiced "urgent support" for the "Human Life Protection Act," an bill which would, in the event that Roe were overturned, trigger an automatic ban on abortion in the state.

The Georgia and Tennessee heartbeat bills join a growing list of legislation recently passed in other states, some of which the courts have already thrown out.

In January, a district judge struck down Iowa's heartbeat abortion law, which Gov. Kim Reynolds had signed last May. The law had not yet gone into effect because of a legal challenge from the American Civil Liberties Union of Iowa, the abortion provider Planned Parenthood of the Heartland and the Iowa City-based Emma Goldman Clinic, which also performs abortions.

The Kentucky House is considering a heartbeat bill that the Senate passed last month. If the bill becomes law, an examination would be required before an abortion to determine whether the unborn baby's heartbeat can be detected. If so, an abortion would be illegal, unless the mother's health is determined to be in danger.

Ohio lawmakers reintroduced a heartbeat bill last month after former Gov. John Kasich vetoed a previous version in December. Ohio's new governor, Mike DeWine, has reportedly expressed support for the measure.

Missouri lawmakers are currently considering a bill that includes a provision banning abortion if either a heartbeat or brain function can be detected.

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The Arkansas legislature passed the first heartbeat-based abortion ban in 2013, and also voted to override a governor's veto of the bill. The U.S. Court of Appeals for the Eighth Circuit ruled it was unconstitutional and the U.S. Supreme Court declined to hear an appeal.

Maryland, Minnesota, Florida, West Virginia, Mississippi, Illinois, and South Carolina are currently considering heartbeat legislation.