Mississippi Gov. Phil Bryant has signed a bill into law making his state the first in the nation to ban abortions past 15 weeks of pregnancy.

The Republican governor signed House Bill 1510 into law on Monday, drawing an immediate lawsuit from the state’s only abortion clinic – Jackson Women’s Health Clinic – which claims the law is unconstitutional.

“We’ll probably be sued here in about half-hour,” Bryant joked as he signed the bill into law. “That’ll be fine with me. It’s worth fighting over.”

The bill makes exceptions to the 15-week ban if the mother’s life is in danger or the unborn baby has a life-threatening abnormality.

Abortion rights advocates claim the law is unconstitutional because it prevents women from having abortions prior to the stage of viability, when a fetus is able to live outside its mother’s womb.

“The legal standard that the Supreme Court has said is that a woman has the right to end a pregnancy before viability,” said Julie Rikelman, legal counsel for the Center for Reproductive Rights, according to Mississippi Today. “And this ban takes effect well over a month before the fetus is viable, and the Supreme Court has said repeatedly that you just can’t do that.”

However, Jameson Taylor, interim director of the Mississippi Center for Public Policy – a conservative think tank that authored the bill – cited Gonzales v. Carhart, a 2007 Supreme Court case that upheld the federal ban on partial-birth abortions. Taylor explained that viability of the fetus is not the “penultimate standard” as it has been in past years, in part due to medical advances that have allowed prematurely born babies to survive outside the womb earlier.

“What’s important is that this regulation makes rational sense,” he said. “That’s exactly what the courts will be looking at, to what extent does this protect the health of the mother and the life of the unborn child.”

While presenting the measure, Republican state Rep. Andy Gipson cited statistics from the pro-abortion rights Guttmacher Institute that shows a mother’s chances of having serious health risks increase substantially when abortions are performed after 18 weeks, from 0.3 deaths per 100,000 abortions performed prior to eight weeks, to 6.7 deaths per 100,000 abortions after 18 weeks.

Planned Parenthood Southeast Advocates condemned the legislation:

“If Gov. Bryant truly cared about the health and well-being of Mississippi women and families, he would be working to expand access to health care — not taking it away,” said Felicia Brown-Williams, state director for Planned Parenthood Southeast Advocates. “This law was written by politicians, not doctors. (House Bill) 1510 is just the latest in a series of attacks targeting women and access to safe, legal abortion.”

Bryant, however, said he was “proud” to sign the bill into law.

“I pray today we have saved the first life of an unborn child in Mississippi,” Bryant tweeted:

I pray today we have saved the first life of an unborn child in Mississippi. https://t.co/G7YNINWGIL — Phil Bryant (@PhilBryantMS) March 20, 2018

“I was proud to sign House Bill 1510 this afternoon,” the governor also posted on his Facebook account. “I am committed to making Mississippi the safest place in America for an unborn child, and this bill will help us achieve that goal.”