Oklahoma Republican Governor Mary Fallin makes remarks before the opening of the National Governors Association Winter Meeting in Washington. February 22, 2014. Reuters

The Oklahoma Supreme Court ruled Tuesday that a state bill that would put new restrictions on abortion providers is unconstitutional.

In a unanimous opinion, all nine justices rejected the law on the grounds that it violated the state's requirement that bills have only one subject. One provision would have allowed unannounced, warrantless searches of abortion providers. Another would have required clinics to send fetal tissue samples to the Oklahoma Bureau of Investigation during procedures where the patient is younger than 14.

Oklahoma Governor Mary Fallin speaks at the First Baptist Church of Moore community memorial service following the large tornado in Moore, Oklahoma May 26, 2013. Reuters

Gov. Mary Fallin signed Senate Bill 642 in June 2015, after it passed in the House, 70-5, and the Senate, 40-5, prompting the Center for Reproductive Rights to file a lawsuit. The organization has challenged restrictive reproductive health measures in Oklahoma eight times over the past four years.

"Today's decision is a critical victory for Oklahoma women and their doctors," said Nancy Northup, the CEO of the Center for Reproductive Rights, in a press release on the organization's website. "They will no longer face the threat of criminal prosecution simply for providing safe and legal health care to their patients."

The press release added that the law was "nothing but a cynical attack on women's health and rights by unjustly targeting their trusted health providers."

Oklahoma has long had a tenuous relationship with reproductive laws. In September, the first new abortion clinic in 40 years was opened in the state. According to the Guttmacher Institute, 96 percent of Oklahoma counties in 2011 did not have an abortion clinic.

The state also has extensive abortion restriction measures on the books. Public funding is available only in cases of rape, incest, or danger of death. Before undergoing an abortion, women in Oklahoma must receive counseling from the state that is designed to discourage abortions and are required to wait 24 hours before having the procedure.

Abortion rates in the state have decreased steadily since 1991.