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.”