*Editor's note: This story has been updated with comment from Joe Pojman, executive director of Texas Alliance for Life.

They're pushing a boulder up a hill in the conservative Texas Legislature. But three House Democrats remain laser-focused on repealing the 24-hour waiting period for abortion imposed by the state’s 2011 sonogram law.

“This 24-hour waiting period has proven to be ineffective, unnecessary and cruel,” state Rep. Jessica Farrar, a Houston Democrat and the chairwoman of the Texas House Women's Health Caucus, said at a Thursday press conference. “It does not change a pregnant Texas woman’s decision.”

Texas’ abortion sonogram law requires a doctor to perform a sonogram on a woman 24 hours before she can receive an abortion. During the sonogram, the physician must play the heartbeat aloud and describe the development of the fetus.

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Proponents of the sonogram law have argued that the waiting period is intended to help pregnant women thoroughly consider their decisions and not be rushed through the process.

Joe Pojman, executive director of Texas Alliance for Life, said the group opposes efforts to repeal the 24-hour waiting period because it is important for women considering an abortion to have “enough time” to weigh the risks and benefits of having an abortion.

Those who oppose the law say it does little to improve reproductive care and instead creates obstacles for women seeking the abortion.

Calls were not immediately returned from representatives of two of the state's most active anti-abortion groups.

Farrar’s House Bill 709, which was filed in January, would not repeal the requirement that a doctor perform a sonogram before an abortion is performed. It would only remove the provision of the law that requires the sonogram to take place 24 hours before an abortion — which abortion rights advocates say is an obstacle for low-income women who struggle with transportation and child care, and face an already dwindling number of clinics.

Farrar acknowledged that there isn’t enough support in the Legislature to repeal the measure. 

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“That doesn’t stop us from continuing to talk about this, because the worst thing that can happen is that we all become silent,” Farrar said. “I think history has shown that because people are vocal over time, eventually you have success.”

The 24-hour waiting period bill is part of a package of women’s health legislation filed by Farrar, state Rep. Mary González, D-Clint, and state Rep. Donna Howard, D-Austin. Those lawmakers are leading a policy campaign to improve reproductive care in Texas. The other bills include measures allowing more comprehensive sex education in Texas schools and carving out a “professional judgment exception” that would give medical professionals performing abortion-related services room to circumvent some state requirements. 

Farrar filed a similar 24-hour waiting period bill during the 2013 legislative session, but it died in committee. She said the waiting period is even more burdensome now than it was last session because of the recent closure of so many clinics.

After lawmakers passed strict abortion restrictions in 2013, all but 18 of the 41 abortion clinics operating in Texas before the law’s passage shut their doors, according to the Texas Policy Evaluation Project at the University of Texas at Austin. The abortion law known as House Bill 2, which is being challenged in court, requires facilities that perform abortions to meet the same hospital-like standards as ambulatory surgical centers. This includes minimum sizes for rooms and doorways and additional infrastructure like pipelines for anesthesia.

If that requirement is upheld, fewer than 10 abortion clinics in Texas would remain in operation, leaving women west or south of San Antonio anywhere from 150 to 500 miles away from a Texas abortion facility.

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