Fulton County Superior Court Judge Doris Downs on Friday halted a measure from taking effect in January that would prohibit most abortions after 20 weeks. She will rule later on the merits of the case.

The law, passed in the closing hours of this year’s legislative session, bans abortions beyond 20 weeks unless there are specific threats to the mother’s health or the fetus has a condition that means almost certain death after birth. It was the state Legislature’s most sweeping attempt to limit abortion in years.

It was quickly targeted by the Georgia branch of the American Civil Liberties Union, which filed a lawsuit seeking to overturn the law filed on behalf of three doctors. It claimed physicians would have to face the “untenable choice” of risking prison time to provide the care their patients seek.

Anti-abortion groups, meanwhile, welcomed the ACLU lawsuit as a potential stepping-stone to reverse the 1973 U.S. Supreme Court decision that legalized abortion. They say a fetus can feel pain at 20 weeks, therefore the state has an interest in protecting it. And state attorneys argued that blocking the law would defy the will of Georgia’s lawmakers.

The Georgia Attorney General’s office did not immediately comment on the judge’s ruling. Chad Brock, a staff attorney with the ACLU, said he was glad Downs halted the restrictions, if only temporarily, and urged lawmakers to pass new measures that would instead increase access to health services.