Women who opt to get an abortion in Arizona within their first two months of pregnancy may soon find themselves on the receiving end of some unusual advice from their doctors. A medical abortion, which works within the first nine weeks or so of gestation, involves taking two pills within a few days of each other. This week Arizona lawmakers passed a bill that would require doctors who perform such abortions to tell their patients that if they reconsidered their abortion after taking their first pill, they should return to the doctor for a procedure that can allegedly "reverse" the abortion.

The bill would also prohibit women from buying insurance plans that cover abortions on the federal health exchange.

"This is a great day for women in Arizona who are considering getting an abortion to get all the facts they need and a great day for Arizona taxpayers," Cathi Herrod, president of the Center for Arizona Policy, a conservative group that backed the bill, told Reuters.

Women's-rights and doctors' groups beg to differ. Pro-choice organizations are peeved about the abortion coverage exclusion. But even gynecologists, who tend to be more reluctant about mobilizing on abortion legislation, are up in arms over this bill. The American Congress of Obstetricians and Gynecologists urged its members on Twitter to pressure Arizona governor Doug Ducey to veto the measure.

The reason, the group says, is that this kind of abortion "reversal" isn't just scientifically unproven, it's also dangerous. And it could leave doctors liable for giving patients shoddy medical counseling.

"There is no science to support this," Arizona-based gynecologist Ilana Addis told me. "ACOG does not support advising women on treatments that are not evidence-based. These women would be unknowing and unwilling guinea pigs."

A medical abortion involves first taking a dose of a medication called mifepristone, which blocks progesterone, a hormone that's necessary for an early pregnancy to thrive. One to three days later, the woman would take misoprostol, which causes uterine contractions and, ideally, expels the pregnancy.

Under the Arizona bill, doctors would tell patients that, should they change their minds after they take the mifepristone but before they take the misoprostol, it's not too late to "reverse" it. The reversal entails receiving a large dose of progesterone, the theory being that the extra hormone will override the progesterone-blocking mifepristone and ensure a healthy pregnancy.

It's rare for women to regret their abortions because obstetricians are advised not to perform the procedure on patients who are unsure, Addis said. Studies show about 95 percent of women who terminate their pregnancies later say it was the right decision.

The reversal procedure is based largely on the findings of a San Diego pro-life gynecologist named George Delgado. His clinic is behind the site "Abortion Pill Reversal," where visitors are greeted by stock photos of sad-looking women in darkened rooms. "I wish I could go back and change things," says one text overlay. "I wish I never did it."

Under "success stories," Delgado tells the story of a woman named Rhonda, whom he treated with progesterone after she regretted taking mifepristone and talked with a priest. Her fetus was given a second chance, he writes, "a second chance she feels was by the grace of God." The Arkansas Right to Life site claims 200 physicians nationwide are willing to perform the same procedure.

Last year, a pro-life clinic in Iowa began administering the progesterone treatments after its medical director learned about the technique through Human Life International, a Catholic organization.

“Because of our close proximity to Planned Parenthood [located directly across the street], we knew that there would be a woman who would take that first pill and want to reverse the procedure,” Vicki Tyler, the executive director of the Women’s Choice Center in Iowa told Vocativ. “And shortly after we began providing the treatment, we received our first phone call, so we know the demand is there.”

The abortion-reversal idea is included in the 2015 legislative guide of Americans United for Life.

What's puzzling about this measure, regardless of one's opinion on abortion, is that the progesterone dose appears to be completely unnecessary. Women who only take the first pill already have a 30 to 50 percent chance of continuing their pregnancy normally, according to ACOG. The progesterone advice is based on a study by Delgado in which he analyzed six case studies of patients who regretted their abortions and were given progesterone. Four out of the six patients went on to deliver healthy infants. In other words, the limited evidence we have suggests that taking progesterone does not appear to improve the odds of fetal survival by much. The abortion pill binds more tightly to progesterone receptors than progesterone itself does, one reproductive researcher told Iowa Public Radio, and thus the hormone surge is unlikely to do much of anything.

As Cheryl Chastine, an abortion provider at South Wind Women’s Center in Kansas, put it recently, "Even if these doctors were to offer a large dose of purple Skittles, they’d appear to have ‘worked’ to ‘save’ the pregnancy about half the time.”

That's why, on the small chance that a woman does regret her abortion midway through, ACOG-affiliated doctors say they would simply tell her not to take the second pill.

Addis cautions that it's generally not a good idea to give women false hope that they can reverse their abortions. But more importantly, a large dose of progesterone does have side-effects that any women seeking these "reversals" would needlessly endure. "There can be cardiovascular side effects, glucose tolerance issues, it can cause problems with depression in people who already had it," Addis said. "And there are more annoying things, like bloating, fatigue, that kind of stuff. It's an unpleasant drug to take."

An abortion is a difficult, life-changing decision, and it's not one most women take lightly. Giving women hope that a medically untested procedure can save their unborn babies doesn't make that choice any easier. But then again, perhaps that's the point.