A brain-diseased woman was undergoing a long, difficult abortion procedure in a California hospital yesterday, ending her parents' search for someone to do the operation after they learned that she had been raped.

The difficult, late-stage abortion was attempted on Laura Eldridge, 35, because doctors thought it was necessary "to save her life," the family's lawyer, Fred DeLisio, said yesterday afternoon. Eldridge was thought to be at least 21 weeks pregnant, DeLisio said.

["They have run into complications," DeLisio told United Press International. "Her condition is serious. I can't tell you the medical details, but I know it began as a labor-induced procedure . . . . We're all waiting to see."]

Earlier, in a telephone interview, DeLisio said, "Her parents were led to believe it's a life-endangering situation to have a daughter with brain disease, totally incapacitated and incoherent, who is five months pregnant." He said Eldridge weighs only about 75 pounds.

Eldridge was admitted Monday to the University of California Irvine Medical Center in Orange, Calif., and the lengthy abortion procedure began that night, he said. The procedure can take more than a day, he said.

The hospital declined to release information about the patient's status.

DeLisio said that over the weekend the family desperately searched for an institution willing to do the abortion.

Eldridge has spent more than three years in restraints in nursing homes. She suffers from a nervous-system disorder thought to be Huntington's chorea, a rare hereditary disease that causes mental deterioration and involuntary jerky movements.

Her pregnancy was discovered only last week, and a rape investigation is under way at the Mirada Hills Convalescent and Rehabilitation Hospital where she was a patient.

DeLisio said that a judge gave Eldridge's mother, Helen Stegmoyer, legal standing Friday to make medical decisions for her daughter. The lawyer said that Eldridge, who has an 11-year-old son from an earlier marriage, was not aware of what was happening. She is "incoherent, doesn't recognize people, she can't talk" because of her nervous-system disease, he said.

Some anti-abortion groups have protested the abortion, he said, but "it was within the prescribed period" allowed under the law.

Abortions after the 21st week of pregnancy are rare, accounting for less than 1 percent of the 1.5 million abortions performed in the United States each year, according to the federal Centers for Disease Control in Atlanta.

Such abortions generally involve injecting a solution into the uterus to induce labor, a process that is usually completed within 24 hours but may take longer, depending on the chemicals or hormones used to manage the labor, the CDC's Dr. David Grimes said.

Although the abortion can be dangerous to a woman in poor health, a Caesarean section would generally be considered even riskier, Grimes said. Although declining to comment on this specific case, he noted that if such a pregnancy were allowed to continue, both the mother and the fetus would be endangered.