State senator Wendy Davis is surrounded by media after the Democrats defeated the anti-abortion bill SB5
The block by democrats on Wednesday came after a marathon speech in the capitol caused some republican supporters of the bill to cast votes past a midnight deadline.
Democratic senator Wendy Davis spoke for more than 10 hours on Tuesday in a bid to run out the voting window on a measure that would place a ban on abortions after 20 weeks of pregnancy.
Republican Governor Rick Perry, a strong opponent of abortion, could still revive the proposal by calling the legislature into a new special session.
Davis's filibuster attempt stalled about two hours ahead of the deadline over a complaint that she had violated rules.
The Republican-controlled Senate then began voting on the bill, amid protests from spectators.
Republican Lieutenant Governor David Dewhurst, after meeting with lawmakers, said some of their votes came in after midnight local time, the effective end of the 30-day special session.
Dewhurst bemoaned the "unruly mob" at the capitol, according to the Dallas Morning News. The bill called for stricter standards for abortion clinics.
Making history
Republican backers said it would protect women's health and that the ban on late-term abortions would protect fetuses, based on disputed research that suggests fetuses feel pain by 20 weeks of development.
Opponents said it would force nearly all Texas abortion clinics to close or be rebuilt.
"This fight showed once again that we are all better off when women and their doctors – not politicians &ndash are the ones making medical decisions," said Cecile Richards, president of Planned Parenthood Action Fund.
"We made history tonight, but we know this isn't the end of the fight to protect women's access to health care in Texas."
Marathon speech
Davis, who began speaking at 11:15am local time, was prevented by procedural rules from deviating off-topic or taking a break by eating, leaning against her desk, sitting down or using the rest room.
Republicans tried to disrupt her by charging that she had meandered off-topic; this included a protest when a colleague of Davis's helped her to adjust a back brace.
Davis whittled away chunks of time by reading testimony and messages from women and others decrying the legislation, reciting previously suggested changes to the bill and tapping into her own past as a single mother at 19.
She said the bill would have choked off her own access to a local Planned Parenthood clinic.
"I was a poor, uninsured woman, whose only care was provided through that facility. It was my medical home," said Davis (50) several hours into her speech.
Lieutenant Governor Dewhurst, who is Senate president, suspended the filibuster after about 10 hours, to cries of "let her speak" from supporters.
Democrats appealed the ruling, sparking a row over parliamentary rules.
After the session, Davis said on social media: "An incredible victory for Texas women and those who love them."
Nationwide debate
The US Supreme Court legalised abortion nationwide in 1973, but conservative states have enacted laws in recent years that seek to place restrictions on the procedure, especially on abortions performed late in pregnancy.
Twelve states have passed 20-week bans, including two states where the bans take effect later this year, according to the Center for Reproductive Rights.
Courts have blocked the bans in three of the 12 states – Arizona, Georgia and Idaho.
Earlier this month, the republican-controlled US House of Representatives passed a bill banning abortions 20 weeks after fertilisation.
The measure is extremely unlikely to become law because Democrats control the US Senate and the White House.
Simmering debate
The Texas proposal would allow exemptions for abortions to save a woman's life, and in cases of severe fetal abnormalities.
"In Texas, we value all life, and we've worked to cultivate a culture that supports the birth of every child," Perry said.
The abortion debate simmers elsewhere in the United States.
North Dakota's only abortion clinic filed a federal challenge on Tuesday to a new state law, the most restrictive in the country, that would ban procedures to end pregnancy once a fetal heartbeat can be detected, as early as six weeks.
A Philadelphia jury last month convicted abortion doctor Kermit Gosnell of murdering three babies during abortions at a clinic in a high-profile case that focused national attention on late term abortions. – Reuters