As is usually the case in abortion politics, the talk on both sides is forceful.

“It’s tragic when a woman makes a decision to have an abortion without knowing all the facts,” said Cathi Herrod, president of the Center for Arizona Policy, a conservative organization that was a leading supporter of the legislation. “We know children have been born. We know women have been spared the heartache of abortion. There’s no downside to this. Where’s the harm in informing a woman that it could be reversible?”

On the other side, Jodi Liggett, the public policy director of Planned Parenthood Arizona, called the new law “dangerous and quite simply outrageous.” She said: “Arizona women trust their physicians. Extreme policy makers are preying on this trust in order to further bad medicine, all in the name of politics, and not science.”

In a drug-induced abortion, the woman first takes mifepristone, a drug designed to end a pregnancy of less than seven weeks, followed about two days later by the drug misoprostol. Dr. Delgado, a family physician and medical director of Culture of Life Family Services in San Diego, says that by giving a woman progesterone, a hormone, before she takes the second drug, the abortion can be reversed.

Dr. Delgado started a website explaining the method because, he said, women were not being told by their abortion providers that it was an option, or, if they were informed, they were told that a reversed abortion could lead to birth defects. He published an article in the December 2012 issue of Annals of Pharmacotherapy in which he said that four out of the six women in his study who took progesterone after taking mifepristone were able to carry their pregnancies to term. He said he has since documented 87 cases where a woman gave birth to a healthy child and 75 where women were still pregnant after being given the progesterone.

But Dr. Delgado’s findings have faced serious scrutiny from the medical community.

“It has no data behind it, absolutely no science to show that this is an effective method,” said Dr. Ilana Addis, the chairwoman of the Arizona section of the American Congress of Obstetricians and Gynecologists. The organization said that in 30 percent to 50 percent of cases in which a woman takes only mifepristone, the pregnancy will continue, meaning the progesterone could have had little effect.