Texas Republican State Senator Glenn Hegar, one of the sponsor of the abortion bill SB1, speaks during an anti-abortion rally at the State Capitol in Austin, Texas, July 8, 2013. [Photo/Agencies]

Only five out of 42 clinics in Texas qualify as ambulatory surgical centers, and they are in major metropolitan areas. Many clinics would need to relocate to meet ventilation requirements and to have the space required for operating rooms and hallways.

Opponents of the bill say the new requirements are unnecessary and would force most Texas abortion clinics to close. Supporters of the bills say they want to reduce access to abortion and improve women's health care. Texas health officials report that 72,240 abortions performed in the state in 2011, including 374 that happened after 20 weeks.

The 20-week ban is based on the scientifically disputed claim that a fetus can feel pain by that point and thus, deserves protection from abortion.

Other states have passed similar restrictions, including some that are being challenged in court, but Texas has been at the center of the national abortion debate since a Democratic state senator succeeded in preventing the Legislature from passing the new restrictions last month by staging a nearly 13-hour filibuster on the session's last day.

Perry called lawmakers into a new 30-day special session to take up the bill again and activists on both sides have kept up a steady presence at the Capitol.

Last week, a House panel heard eight hours of testimony from about 100 witnesses but cut off thousands more who had registered. Unlike the House, which has online registration, the Senate required witnesses to register in person.

Senate committee chairwoman Sen. Jane Nelson, R-Flower Mound, allocated more time for testimony said she still needed to place a time limit. Nelson said the panel would not vote at the hearing's conclusion.

"We're going to run straight through the night," Nelson said.

Before any of them started, Sen. Bob Deuell, R-Greenville, called abortion an "American holocaust" and placed two pairs of infant sneakers at his desk as a reminder of fetuses that were aborted before they could be born.

During the hearing, activists from both sides roamed the Capitol, packed waiting rooms and waited for their chance to speak. Security was tight, but the gathering lacked the tension of the previous week when demonstrators chanted, sang and prayed their way around crowded hallways.

Even with only a short time allowed, several women told emotionally wrenching stories of regrets about having abortions or delivered passionate defenses of a right to choose whether to carry a pregnancy to term.

Vanessa Riley, who opposed the bill, said she had an abortion after learning in her second trimester that the child she was carrying had severe developmental problems.

"My husband and I made the most ethical decision we could," Riley said. "I was preventing pain, not causing it."

At the anti-abortion rally, Attorney General Greg Abbott — who has used a wheelchair since he was 26, when a tree collapsed on him during a jog, leaving him paralyzed in both legs — said he would "stand for life" with demonstrators in spirit.

"You don't have to stand to fight for life," said Abbott, who is expected to soon announce if he will run for governor in 2014.