More than 600 women’s rights protesters crowded into the Texas Capitol on Sunday to watch Democrats begin a series of parliamentary maneuvers to stop the Republican majority from passing some of the toughest abortion restrictions in the country.

Democrats began the session by pointing to a technicality that delayed voting on any bills for 4½ hours. The forced adjournment burned up precious time since the session ends at midnight Tuesday and the abortion bill still needs to go back to the Senate for final approval.

While several bills are under consideration, the only one with a real chance is Senate Bill 5, an omnibus bill that would ban abortions after 20 weeks, require that they take place in surgical centers and restrict where and when women can take abortion-inducing pills. Part of the new law would also require doctors performing abortions to have admitting privileges at a hospital within 30 miles.

Supporters say the measures are intended to protect women’s health, but opponents call them needless regulations to make abortions more difficult to obtain. If passed, 37 out of 42 abortion clinics in Texas would have to close and undergo millions of dollars in upgrades.