LITTLE ROCK, Ark. — A federal judge on Tuesday blocked an Arkansas law banning nearly all abortions in the state while she hears a challenge to its constitutionality.

U.S. District Judge Kristine Baker issued a preliminary injunction preventing enforcement of the law, which was set to take effect on July 28. The measure passed by the majority-Republican Legislature and signed by GOP Gov. Asa Hutchinson.

The ban allows the procedure to save the life of the mother in a medical emergency and does not provide exceptions for those impregnated in an act of rape or incest.

Baker called the law “categorically unconstitutional” since it would ban the procedure before the fetus is considered viable.

“Since the record at this stage of the proceedings indicates that women seeking abortions in Arkansas face an imminent threat to their constitutional rights, the Court concludes that they will suffer irreparable harm without injunctive relief,” she wrote.

The U.S. Supreme Court in May agreed to take up a case about whether states can ban abortions before a fetus can survive outside the womb, a showdown that could dramatically alter nearly 50 years of rulings on the procedure.

That case, which focuses on a Mississippi law banning abortion 15 weeks into a woman’s pregnancy, probably will be argued in the fall, with a decision likely in the spring of 2022.

Republican lawmakers in Arkansas and several other states, encouraged by former President Donald Trump’s appointments to the high court, enacted new abortion bans even before that case was announced.

The bans were pushed by Republicans who want to force the U.S. Supreme Court to revisit its 1973 Roe v. Wade decision legalizing abortion nationwide.

The American Civil Liberties Union and Planned Parenthood, which had challenged the outright ban, hailed Baker’s decision. The groups are suing on behalf of Little Rock Family Planning Services, a Little Rock abortion clinic, and Planned Parenthood’s Little Rock health center. The groups are also representing a doctor who works at the Planned Parenthood clinic.

“We’re relieved that the court has blocked another cruel and harmful attempt to criminalize abortion care and intrude on Arkansans’ deeply personal medical decisions,” ACLU of Arkansas Executive Director Holly Dickson said in a statement.