The senators spent the morning trying to determine whether the majority-Republican senate managed to push through a vote on the bill, which would restrict abortion, ahead of the midnight deadline.
Sen. John Whitmire, D-Houston, says the bill passed at 12:02 a.m. If the passing time is after midnight, the vote may not withstand legal scrutiny.
"It's pretty conclusive that it didn't pass," Whitmire said.
Senate Republicans briefly claimed victory Tuesday evening, but the late-night vote was rendered moot because it did not follow legislative procedures.
It was a glint of victory for Democrats after the party's Wendy Davis filibustered the bill for nearly 13 hours. Texas' Lieutenant Governor ruled at 3:01 a.m. that Davis stood long enough to kill the bill.
SB 5 is written by Republican state senator Glenn Hagar and would make abortion illegal after 20 weeks. It would also establish requirements for abortion facilities, which supporters say would make the procedures safer for women and their unborn babies.
Opponents of the bill say the legislation is too stringent, and would shut down most of the abortion facilities in Texas. Some analysts have called the proposed abortion restrictions the toughest in the nation.
Republican senators voted 19-10, but by then the clock had ticked past midnight. Under the terms of the state Constitution the bill could not be signed, enrolled or sent to the governor. Conservative lawmakers tried to find a way to derail Davis' filibuster but were unable to end the debate.
Lt. Gov. David Dewhurst said he was frustrated with the night’s results, after officially declaring the bill could not be enrolled.
“An unruly mob using Occupy Wall Street tactics” derailed legislation that he said was intended to protect women and babies.
"I didn't lose control of what we were doing," he said. "We had an unruly mob."