Oklahoma Gov. Mary Fallin vetoed a bill on Friday that would have made it a felony for doctors to perform an abortion.

The legislation, which was the first of its kind, as NPR's Jennifer Ludden reported Thursday, would have effectively eliminated abortion in the state. Oklahoma lawmakers passed the bill on Thursday, as the Two-Way reported.

Fallin's office issued a press release saying she vetoed the bill because it was "vague and would not withstand a criminal constitutional legal challenge."

It continued:

"Fallin is the most pro-life governor in the nation. She has signed 18 bills supporting pro-life values and protecting the health and lives of mothers and their unborn children."Senate Bill 1552 would have made it a felony for physicians to perform abortions. It also contained a provision to revoke their medical licenses unless the abortion was necessary to save the life of the mother." 'The bill is so ambiguous and so vague that doctors cannot be certain what medical circumstances would be considered 'necessary to preserve the life of the mother,' Fallin said." 'The absence of any definition, analysis or medical standard renders this exception vague, indefinite and vulnerable to subjective interpretation and application,' she wrote in her veto message."

As Jennifer reported Thursday, abortion rights groups said the bill "is unconstitutional, a direct violation of Roe v. Wade," the 1973 Supreme Court decision that legalized abortion nationwide, and predicted it would be struck down by the courts if it were signed into law.

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