TOPEKA, Kan. (AP) — Republican lawmakers in Kansas narrowly failed Wednesday to override Democratic Gov. Laura Kelly's veto of a bill requiring abortion providers to tell patients about a disputed treatment to stop a medication abortion after it's been started.

It was a second major loss in less than a week for abortion opponents in a state where they became accustomed to enacting new restrictions easily under Kelly's conservative GOP predecessors before she took office in January. The Kansas Supreme Court ruled Friday that the state constitution protects abortion rights, potentially opening up existing restrictions to legal challenges.

The Republican-controlled Senate voted 27-13 to override Kelly's veto, exactly the two-thirds majority required. However, in the GOP-controlled House, the 82-43 vote left abortion opponents two votes shy, stunning top Republicans who had expected to prevail.

"This is unnecessary legislation that would interfere with the relationship between women and their physicians," Kelly said in a statement after the House vote. "It forces health care providers to adhere to a government mandate not adequately supported by medical science."

Medication abortions using Mifepristone, also known as RU-486, are the most common way of terminating a pregnancy in Kansas, accounting for 61% of the total last year, according to statistics from the state health department.

The bill would require clinics to display a notice about the possibility of a medication abortion "reversal," and physicians would have to tell a patient in writing that one could be stopped. A clinic that failed to post a sign could be fined $10,000, and a doctor who failed to notify a patient could be charged with a misdemeanor for a first offense and a felony for a second.

Abortion opponents argued that the measure would ensure women who harbor doubts about ending their pregnancies will learn that they can take the hormone progesterone to stop a medication abortion after taking the first of two pills.

Eight states with Republican governors have enacted such laws, starting with Arkansas in 2015. Oklahoma's GOP governor signed a measure last week.

"It merely gives them the information to make the most informed decision for their health and that of their unborn child," said Rep. Renee Erickson, a Wichita Republican.

Action on the "reversal" bill in Kansas came after other states, including Kentucky, Mississippi and Ohio, moved to ban abortions when a fetal heartbeat is detected, as early as the sixth week of pregnancy. Kansans for Life, the state's most influential anti-abortion group, has long favored an incremental approach and restrictions that it believes will survive court challenges.

But it's no longer clear what would survive court challenges in Kansas after the state Supreme Court's sweeping ruling last week. The court said the state constitution's Bill of Rights grants a right to "control one's own body" and to decide whether to continue a pregnancy.

Senate President Susan Wagle, a conservative Wichita Republican and a vocal supporter of the bill, acknowledged that the state courts could strike it down. But she said trying to override the veto still was appropriate.

The vote in the House on overriding the veto was even closer than the tally indicated. Rep. Blake Carpenter, a conservative Wichita-area Republican, switched to voting against the override at the last moment — so that under the House's rules, he had the right to ask for the vote to be reconsidered.

With abortion foes really one vote short, the only Republican truly opposing an override was moderate Kansas City-area Rep. Jan Kessinger.

He joined four Democrats who had voted for the bill previously in opposing an override of Kelly's veto. Afterward, House Majority Leader Dan Hawkins, a conservative Wichita Republican, went back to Kessinger's desk in an attempt to get him to change his mind. It didn't work and there was no vote to reconsider.

Kessinger said he researched the issue in the weeks between his first vote and the attempt to override the veto. He said he concluded that while the treatment advocated by abortion opponents probably does not hurt women, "This needs some more, solid research."

Hawkins said later: "I'm disappointed that we have one Republican that has stood against the whole caucus. That's not a good thing."

Supporters of "reversal" laws cite a 2018 study led by an anti-abortion doctor and medical school professor in California. They also note that progesterone has been used for decades to prevent miscarriages.

Abortion-rights supporters have said that study is flawed and that progesterone's use for reversing a medical abortion hasn't been adequately tested. The American College of Obstetricians and Gynecologists has disputed the usefulness of the procedure.