By MANNY FERNANDEZ and ERIK ECKHOLM

WACO, Tex. — A federal appellate court upheld some of the toughest provisions of a Texas abortion law on Tuesday, putting about half of the state’s remaining abortion clinics at risk of permanently shutting their doors and leaving the nation’s second-most populous state with fewer than a dozen clinics across its more than 267,000 square miles. There were 41 when the law was passed.

Abortion providers and women’s rights groups vowed a quick appeal to the United States Supreme Court, setting the stage for what could be the most far-reaching ruling in years on when legislative restrictions pose an “undue burden” on the constitutional right to an abortion.

A three-judge panel of the appellate court, the United States Court of Appeals for the Fifth Circuit, in New Orleans, sided for the most part with Texas and the abortion law the Republican-dominated Legislature passed in 2013, known as House Bill 2.

The judges ruled that Texas can require all abortion clinics in the state to meet the same building, equipment and staffing standards that hospital-style surgical centers must meet, which could force numerous clinics to close, abortion rights advocates said.

In addition to the surgical standards, the court upheld a requirement that doctors performing abortions obtain admitting privileges at a hospital within 30 miles of a clinic. The court said that except as applied to one doctor working in McAllen in South Texas, the provision did not put an unconstitutional burden on women seeking abortions.

Texas lawmakers argued that the provisions were intended to improve safety. But major medical associations say these measures do not improve patient safety, and abortion rights advocates say they are really intended to restrict access to abortion.

Under the 1973 Roe v Wade decision and later cases, the Supreme Court has permitted a wide array of abortion regulations, including waiting periods and parental consent for minors, but said states may not impose an “undue burden” on the right to an abortion before a fetus is viable outside the womb.

Throughout the ruling, the Fifth Circuit judges cited the explanations given by the Texas Legislature for what is considered one of the most restrictive abortions laws in the country.

“Texas’ stated purpose for enacting H.B. 2 was to provide the highest quality of care to women seeking abortions and to protect the health and welfare of women seeking abortions,” the Fifth Circuit ruling read. “There is no question that this is a legitimate purpose that supports regulating physicians and the facilities in which they perform abortions.”

But clinic owners, women’s health groups and the American Civil Liberties Union said that if the Fifth Circuit’s decision were to take effect, the results would be “devastating” for women seeking abortions in Texas.

“Not since before Roe v. Wade has a law or court decision had the potential to devastate access to reproductive health care on such a sweeping scale,” said Nancy Northup, the president and chief executive of the Center for Reproductive Rights, whose lawyers were part of the legal team representing the clinics that sued the state. “Once again, women across the state of Texas face the near total elimination of safe and legal options for ending a pregnancy, and the denial of their constitutional rights.”

The decision by the Fifth Circuit, regarded as one of the most conservative federal appellate courts in the country, is expected to take effect in about 22 days. In the meantime, however, the clinics and their lawyers plan to ask the court to stay the decision while they appeal it. If the Fifth Circuit declines, the clinic lawyers said, they will seek an emergency stay from the Supreme Court that would prevent the ruling from taking effect while the Supreme Court considered whether to hear the case.

There are 18 facilities providing abortions in Texas, and if and when the Fifth Circuit’s decision goes into effect, eight clinics will close and 10 facilities are expected to remain open, largely because they are ambulatory surgery centers or have relationships with such centers, according to Dr. Daniel Grossman, an investigator with the Texas Policy Evaluation Project and one of the experts who testified for the clinics in the case. But the fate of at least one of the facilities expected to stay open, a clinic in McAllen in the Rio Grande Valley, remained uncertain.

Lawyers for the Texas clinics that sued the state said about 900,000 reproductive-age women will live more than 150 miles from the nearest open facility in the state when the surgical-center requirement and admitting-privileges rule take effect.

The Fifth Circuit panel found that the percentage of affected women who would face travel distances of 150 miles or more amounted to 17 percent, a figure that it said was not a “large fraction.” An abortion regulation cannot be invalidated unless it imposes an undue burden on what the Supreme Court has termed “a large fraction of relevant cases.”

Previously, a panel of the same federal appeals court ruled that Mississippi could not force its only remaining abortion clinic to close by arguing that women could always travel to neighboring states for the procedure. But the panel in the Texas case on Tuesday held that the closing of a clinic in El Paso — which left the nearest in-state clinic some 550 miles to the east — was permissible because many women had already been traveling to New Mexico for abortions, and because the rule did not close all the abortion clinics in Texas.

In the case of the McAllen clinic, the sole abortion provider in the Rio Grande Valley, Tuesday’s decision held that the distance of 235 miles or more to the nearest clinic did pose an undue burden. For now, at least, the Fifth Circuit panel exempted that clinic from aspects of the surgical-center and admitting-privileges requirements. But Amy Hagstrom Miller, the chief executive of Whole Woman’s Health, which runs the McAllen facility and was one of the abortion providers that sued the state, said the organization was evaluating whether the ruling would permit the clinic to continue operating.

The Texas attorney general, Ken Paxton, called the Fifth Circuit’s decision upholding the law a “victory for life and women’s health.”

“H.B. 2 both protects the unborn and ensures Texas women are not subjected to unsafe and unhealthy conditions,” Mr. Paxton said in a statement. “Today’s decision by the Fifth Circuit validates that the people of Texas have authority to establish safe, common-sense standards of care necessary to ensure the health of women.”