All six women in the Utah Senate walked out in protest and refused to vote before the chamber passed a bill mandating that a woman be shown an ultrasound before receiving an abortion. Republican Sen. Deidre Henderson said the walkout late Tuesday was a spontaneous decision to underscore concerns about the "invasive nature" of the bill.

The six women lawmakers - two Republicans and four Democrats - would not have changed the outcome. Five Republican men voted against the measure that passed 16-7.

Henderson said she opposes abortion but the mandatory ultrasound proposal went too far. It would require showing a pregnant woman images and making the fetal heartbeat audible, if possible.

In this Feb. 27, 2020, file photo, Republican Sen. Deidre Henderson poses for a portrait at the Utah State Capitol, in Salt Lake City. Rick Bowmer / AP

Women now get an ultrasound before abortions, but providers aren't required to show them the results. Under the bill, doctors could be fined $100,000 or more if they perform the procedure without showing an ultrasound.

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"It was sisterhood coming together, so that's what it is," Democratic Sen. Luz Escamilla told CBS affiliate KUTV. "We felt really concerned about how invasive that is."

Republican Sen. Curtis Bramble, who is sponsoring the bill in the Senate, said a woman could look away from the images or not listen to the heartbeat.

"If you are going to take the life of a child, if you are willing to terminate that life through an abortion, it seems appropriate that you get the best information about the development, the stage of development, heart beat - we are talking about a human being," Bramble told the Deseret News.

Before the vote, Henderson successfully added an amendment prohibiting a transvaginal ultrasound, a procedure she called "incredibly invasive."

The bill now returns to the House for consideration of the amendment. Three medical organizations have asked Republican Gov. Gary Herbert to veto the proposed ultrasound mandate, and a fourth has taken a neutral position, according to the Salt Lake Tribune.

Democratic Senate Minority Leader Sen. Karen Mayne said she was sad that women had to tell their own life stories as they spoke against the bill, and yet their male colleagues didn't appear to believe the proposal was too invasive.

"Why do we have to explain to you why this is not right? Why?" she said.