Any woman who wants an abortion in Nebraska could have to receive information on how to “reverse” the procedure — something experts aren’t sure is scientifically possible.

The Nebraska Legislature passed a bill Thursday night that mandates the state’s Department of Health and Human Services provide the information, just in case a woman changes her mind about undergoing a medication abortion. The bill now heads to the desk of Republican Gov. Pete Ricketts, who has openly declared Nebraska a “pro-life” state, according to the Lincoln Journal-Star.

If Ricketts signs the bill into law, Nebraska will become the fifth state to require people be informed about the possibility of abortion reversal. But Arkansas, Idaho, South Dakota, and Virginia require doctors to tell women they can reverse their abortions.

It’s not yet clear how the Nebraska Department of Health and Human Services plans to convey the information, according to the Lincoln Journal-Star, but the agency might put the information on its website.

Lawmakers debated for over 10 hours Thursday about the merits of abortion reversal, which supposedly works by taking repeated doses of progesterone, a hormone that helps sustain pregnancy, in order to reverse the effects of a pill called mifepristone. (To end a pregnancy, people typically first take mifepristone and then take misoprostol several hours later.)

It’s probably safe to take the repeated doses of progesterone, but it’s not at all clear whether they work to “reverse” abortions. Researchers at the University of California, Davis, are currently leading what might be the first study on abortion reversal that uses randomized, double-blind testing and placebos to test the effectiveness of progesterone.

“The tragedy, in a lot of this, is when legislators get involved in things that aren’t proven and then legislate requirements that impede care or are basically, potentially, lies,” Mitchell Creinin, a professor at UC-Davis, previously told VICE News.

But some Democratic Nebraskan lawmakers don’t want the effectiveness of progesterone tested on women in the state unless it’s scientifically proven to work.

“Patients who want to continue their pregnancy should not be guinea pigs, and the Nebraska Legislature should not sanction that,” state Sen. Megan Hunt, an opponent of the bill, said earlier this month.