KNOXVILLE, Tenn. — UPDATE 3/7/19:

The controversial "heartbeat bill" that would ban abortions after a fetal heartbeat is detected was passed by Tennessee House of Representatives Thursday morning. 

There are amendments that were filed to the bill and 10News is still working to identify those.

Click here to read the full version of the bill.

Some of the amendments change the language from "unborn child was not viable" to "the pregnancy was not viable". 

The bill passed 65-21. Last month, the House Health Committee voted 15-4 to send the legislation to the House floor for a full vote. 

It still needs to pass in the Senate before it can be sent to the governor's desk, where it could still be vetoed. 

The so-called "heartbeat bill" requires an ultrasound before a woman has an abortion and makes the procedure illegal if a heartbeat is detected. 

Dr. Kim Fortner with the University of Tennessee Medical Center says a fetal heartbeat is typically able to be detected around six weeks after conception. 

She says a fetus is typically smaller than a blueberry at that stage of development.

The U.S. Supreme Court has ruled similar bills unconstitutional because it says abortion before a fetus is viable is allowed. 

The other time the 'heartbeat' bill had been proposed in Tennessee back in 2017, Tennessee Right to Life had taken the same stance -- supporting the purpose but calling the strategy a 'step backward' for pro-life efforts in the state, saying the ban would inevitably be deemed unconstitutional.   

ORIGINAL STORY 3/6/19:

The Tennessee Right to Life organization has joined the state's Catholic bishops in not supporting controversial legislation that would effectively ban abortions from six weeks after conception. 

The so-called "heartbeat bill" requires an ultrasound before a woman has an abortion and makes the procedure illegal if a heartbeat is detected.

Dr. Kim Fortner with the University of Tennessee Medical Center says a fetal heartbeat is typically able to be detected around six weeks after conception. 

She says a fetus is typically smaller than a blueberry at that stage of development.

RELATED: Tennessee lawmakers advance fetal heartbeat bill

Will Brewer, the legislative liaison for Tennessee Right to Life, says the organization supports the intention of the legislation but does not believe it has a chance of going into effect.

"We feel there is stronger pro-life legislation to be passed and this will ultimately hurt the movement going forward," he said. "It strips current pro-life laws that are currently on the books and it makes no provisions of what happens to those pro-life laws when it’s enjoined or struck down by the courts."

RELATED: Bill would make performing abortions a felony if Roe v. Wade overturns

The other time the 'heartbeat' bill had been proposed in Tennessee back in 2017, Tennessee Right to Life had taken the same stance -- supporting the purpose but calling the strategy a 'step backward' for pro-life efforts in the state, saying the ban would inevitably be deemed unconstitutional.   

The U.S. Supreme Court has ruled similar bills unconstitutional because it says abortion before a fetus is viable is allowed. 

But one of the co-sponsors of the bill, Knoxville Rep. Jason Zachary, says changes in wording make this bill different.  

"We know it will be litigated. However, ours has been amended, we've taken out the word fetus. We've added the word pregnancy," he said. 

He says courts haven't ruled on that wording yet. 

But Brewer says it makes more sense to focus on legislation that has a chance of going into effect. 

"I think that there are certain members of the legislature and certain members of the grassroots movement that want to have their name on a lawsuit that goes to the U.S. Supreme Court," he said. "It would be a better use of our taxpayer money and resources as a state to let Ohio use their resources and their money to fight that battle and help us save money as a state." 

Both Tennessee Right to Life and the state's Catholic bishops say they support another bill called the Tennessee Life Protection Act instead. That bill would immediately ban abortions if Roe v. Wade is overturned.