PHOENIX — Planned Parenthood and a Tucson gynecologist are asking a federal judge to block new rules that will sharply restrict the ability to perform abortions using drugs instead of surgery.

The lawsuit filed late Tuesday contends the regulations limiting the ability of doctors to use RU-486 violate the liberty and privacy rights of patients by imposing “an unconstitutional burden on their right to choose an abortion.” It also says it denies some women the right to terminate a pregnancy through a pill rather than through a surgical procedure, therefore violating patients’ “rights to bodily integrity.”

Attorneys for Planned Parenthood and the Center for Reproductive Rights are asking U.S. District Judge Frank Zapata initially to block the rules from taking effect as scheduled April 1. Eventually they want the rules — and the 2012 law that required the Department of Health Services to enact them — declared illegal.

The fight is over the use of mifepristone, an abortion-inducing drug known as RU-486, and misoprostol, a drug taken at home 24 to 48 hours later to ensure the fetus is expelled.

The 2012 law now being implemented says any medication used to induce an abortion must be administered “in compliance with the protocol authorized by the U.S. Food and Drug Administration,” as outlined in the final labeling instructions for that drug.

In the case of RU-486, that means only through the seventh week of pregnancy. But both Planned Parenthood and Dr. William Richardson, who operates the Tucson Women’s Center, use it into the ninth week.

Taking the drug out of the equation means a woman at that stage of pregnancy would have to undergo a more complicated and expensive surgical procedure.

But the 2012 law also would affect women who are seeking an abortion within the first seven weeks of pregnancy.

The FDA-approved procedure requires a higher dosage of RU-486 administered in two dosages, by a doctor, within 48 hours. That second dose adds about $90 to the cost for women, not counting cost and time of the required second visit a woman would have to make to a clinic to have that second pill administered by a doctor versus being able to take it at home.

“All of these burdens come with no medical benefit whatsoever,” the lawsuit states. Instead, requiring doctors to follow the FDA protocol actually could harm women by requiring them to take three times as much medication as necessary.

And the lawsuit contends the FDA protocols have been shown to be not entirely effective, meaning a woman might then need to undergo surgery to complete the abortion.

Josh Kredit, attorney for the anti-abortion Center for Arizona Policy, which pushed the legislation, said the restriction is justified. He said it is up to the FDA and not individual doctors to decide when and how the drug can be used.

Kredit also claimed abortion providers want to use the two-drug protocol through nine weeks for financial reasons.

“This is Planned Parenthood putting profits above people,” he said. Kredit said the organization has decided to ignore the FDA protocols because women prefer medical abortions and “it’s easier to sell it to them.”

Hundreds of women would be affected if the new rules take effect as scheduled.

Bryan Howard, president of Planned Parenthood Arizona, said his organization performed more than 5,000 abortions in the last full year on women who were in the first nine weeks of pregnancy. He said about half chose medical abortions.

And Howard said that a third of those who went that route actually were beyond seven weeks, meaning a medical abortion would no longer be an option for them.

No one is disputing that the drugs are being used in Arizona in a way not specifically approved by the FDA. But Erie Reuss, an obstetrician and gynecologist who also is on Planned Parenthood’s board, said that is nothing unusual.

He said the FDA always has allowed “off-label” use of all sorts of drugs. And Reuss said the labeling is based on “an outdated FDA protocol” that subsequent medical research has shown is unduly restrictive.

“The law requires physicians to ignore decades of medical research, the opinion of leading medical organizations, and their own clinic experience, and administer medical abortion in an outdated and inferior manner,” the lawsuit says.

Howard, while saying the FDA protocols are out of date, said his organization has not asked the federal agency to revisit them. He said such a request can be made solely by the manufacturer.

This is not the first challenge to the 2012 law. That same legislation also contained a ban on abortions at 20 weeks of pregnancy, a provision struck down by a federal court in a ruling the U.S. Supreme Court let stand.