"The state presents no evidence that a fetus can live outside the mother's womb at twelve weeks," the judge wrote.
By adopting a ban based on a fetal heartbeat, and not the ability to survive, the Arkansas Legislature had adopted the nation's toughest abortion law last March. Two weeks later, North Dakota lawmakers passed a bill restricting abortions at six weeks — or before some women would know they're pregnant. That law is on hold.
In her decision Friday, Wright said only a doctor could determine viability.
"The Supreme Court has ... stressed that it is not the proper function of the legislature or the courts to place viability at a specific point in the gestation period," Wright wrote.
Wright left in place a portion of the law that requires doctors to check for a fetal heartbeat and to notify the pregnant woman if one is present.
Gov. Mike Beebe had vetoed the bill, citing the viability standard. But Republicans, controlling the Statehouse for the first time since Reconstruction, overrode him with a simple majority vote.
"The ruling is what the governor predicted in his veto letter last year," Beebe spokesman Matt DeCample said.
The state attorney general's office said it was reviewing possible next steps. "Today's decision was not a surprise," spokesman Aaron Sadler said.
Bettina Brownstein, who represented two doctors who perform abortions at a Little Rock clinic, said the 12-week ban was "demeaning to women."
State Sen. Jason Rapert who sponsored the fetal heartbeat bill, said he was encouraged that that portion of the measure was upheld.
"Now, anyone who presents for abortion in our state, they're going to be given an opportunity to know if there's a living heartbeat in their womb, and that is a win for the pro-life movement," Rapert said. "When people have to face the reality that there's a living heartbeat in their womb, that will make them rethink about taking the life away from their baby."