Anna Nusslock never expected to be denied an emergency abortion by a hospital in California, a state with some of the strongest abortion rights protections.

In February, Dr. Nusslock, 36, a chiropractor in Eureka, Calif., went to the nearest emergency room, at Providence St. Joseph Hospital, after her water broke just 15 weeks into pregnancy. Doctors said one of the twins she was carrying would not survive and the other had almost no chance, according to medical records. They said that if the pregnancy was not terminated, she could face infection, hemorrhaging and threats to her future fertility.

But because fetal heart tones could still be detected, a doctor at the Catholic-affiliated hospital said the institution’s policy prohibited providing abortion unless Dr. Nusslock’s life was at risk, according to her medical records. After several hours, her husband drove her to the next closest hospital, where she arrived hemorrhaging and passing a blood clot the size of an apple. She expelled one fetus and was rushed into the operating room so the other fetus could be removed, records show.

“I thought I would be safe here from things like this,” Dr. Nusslock said in an interview, “from people taking away choices from me and leaving me in danger.”

Similar situations have occurred in states with abortion bans, but California’s attorney general, Rob Bonta, said in an interview that Dr. Nusslock’s case shows they can happen “even in California, a place that is very strongly pro-choice.”

On Monday, the attorney general filed suit against the company that operates Providence St. Joseph, charging that the hospital violated a California law requiring hospitals with emergency rooms to provide care to prevent not only death, but “serious injury or illness.”