RALEIGH, N.C. — A federal judge has struck down a 1973 North Carolina law that limited abortion to the first 20 weeks of a woman’s pregnancy. U.S. district Judge William Osteen issued a ruling March 25, finding the law unconstitutional.

Although the law banning abortion after 20-weeks gestation has been on the books for decades, it has never been enforced. The decision found that the law, even if not enforced, had a “chilling effect” that harmed constitutional rights.

The law originally included exemptions that permitted an abortion to protect the health of the mother, but a 2015 amendment to the legislation narrowly defined this as when a “major bodily function” would be at risk if the pregnancy continued.

That change prompted abortion advocacy groups, including Planned Parenthood South Atlantic, to file a 2016 suit against the law. Planned Parenthood South Atlantic operates facilities in North Carolina, South Carolina, Virginia and West Virginia.

The Supreme Court has repeatedly found that a woman has a constitutional right to an abortion before fetal viability, and Osteen ruled that the law, even if unenforced, was unconstitutional.

“To this court, the most reasonable inference from such conduct is that defendants hope to ensure the ban remains on the statute books to deter doctors from providing any post-20-week abortions while not actively investigating or initiating any criminal prosecutions under the ban,” wrote Osteen in his decision.

“But if plaintiffs are reasonably deterred from providing these abortions by the mere presence of the ban, they have suffered a potential constitutional injury.”

These actions amounted to what Osteen called the “chilling-effect doctrine,” which is when a law “reasonably dissuades individuals from engaging in constitutionally protected speech for fear of criminal punishment.” The “chilling effect” alone could justify a legal complaint against the law, said Osteen.

With the law struck down, abortion remains legal for any reason in North Carolina until a doctor determines that the unborn child can survive outside of the womb.

The ruling will go into effect in 60 days from March 25, provided it is not further challenged by the state of North Carolina.

Earlier this year, lawmakers in the state attempted to pass legislation to ban abortion after the first trimester of a pregnancy.

Elsewhere in the United States, many states have passed bans on abortion pre-viability, including 15-week or fetal-heartbeat bans. These laws have all been subject to judicial review upon passage, with many being declared unconstitutional.

Multiple judicial decisions against fetal heartbeat laws have prompted many pro-life organizations, as well as the Catholic bishops of Tennessee, to withdraw their support.

If the 1973 Roe v. Wade Supreme Court decision were to be overturned, states would be free to set their own abortion policies. Many states have codified the Roe decision into law in the event it would be overturned, but five states have “trigger laws” that would automatically ban abortion entirely if the case were overturned.