Jackson Women's Health Organization, the only abortion clinic in Mississippi, sued the state after Bryant signed what would have been one of the strictest abortion laws in the U.S., banning most abortions once fetal cardiac activity can be detected, which can be at about six weeks. The clinic said it provides abortions until 16 weeks. Photo by Ashton Pittman

JACKSON, Miss. (AP) — A federal appeals court is keeping a block on a Mississippi law that would ban most abortions as early as about six weeks — a stage when many women may not even know they are pregnant.

A panel of the 5th U.S. Circuit Court of Appeals made the decision Thursday, finding that the law is unconstitutional because it would ban abortion before the point of viability, when a fetus could survive outside of the womb.

The appeals court judges agreed with a district court judge who blocked the law from taking effect in 2019, soon after it was signed by then-Gov. Phil Bryant, a Republican.

The only abortion clinic in Mississippi sued the state after Bryant signed what would have been one of the strictest abortion laws in the U.S., banning most abortions once fetal cardiac activity can be detected, which can be at about six weeks. The clinic said it provides abortions until 16 weeks.

With the addition of conservative justices to the U.S. Supreme Court in recent years, several states have been enacting laws aimed at spurring court challenges that could eventually seek to overturn Roe v. Wade, the court's landmark 1973 ruling that legalized abortion nationwide.

Thursday's decision was the second time in recent months that the conservative 5th Circuit has blocked a Mississippi abortion law. In December, a panel of the appeals court kept a block on a 2018 Mississippi law that would have banned most abortions at 15 weeks, before viability. The state asked the full appeals court to reconsider that decision. In January, the court said it would not do that.

“This is now the second time in two months the 5th Circuit has told Mississippi that it cannot ban abortion,” Hillary Schneller, senior staff attorney at the Center for Reproductive Rights, said in a statement Thursday. “Despite the relentless attempts of Mississippi and other states, the right to legal abortion remains the law of the land.”

In its decision Thursday, the appeals court said the Mississippi clinic and attorneys for the state disagree on when fetal cardiac activity can be detected, with the clinic saying it can happen at six weeks and the state saying it can happen at six to 12 weeks.

“But all agree that cardiac activity can be detected well before the fetus is viable,” the appeals court wrote. “That dooms the law. If a ban on abortion after 15 weeks is unconstitutional, then it follows that a ban on abortion at an earlier stage of pregnancy is also unconstitutional.”

It was not immediately clear Thursday whether Mississippi will appeal the ruling on the six-week ban. State officials said in January that they want the U.S. Supreme Court to consider arguments over the 15-week ban.