Challengers to Texas’ six-week ban on abortions are asking the U.S. Supreme Court to block the measure before it goes into effect Wednesday, after a federal appeals court halted lower court proceedings in the litigation.

The emergency petition from abortion providers in the state, presented to Justice Samuel Alito, says the law “would immediately and catastrophically reduce abortion access in Texas, barring care for at least 85% of Texas abortion patients (those who are six weeks pregnant or greater) and likely forcing many abortion clinics ultimately to close.”