The parents of a 3-year-old boy who was born with severe brain damage were granted $1.3 million yesterday in an out-of-court settlement of a medical malpractice suit brought against Georgetown Univerity Hospital and the doctor who delivered the child.

Under the terms of an agreement signed by U.S. District Court Judge JuneL. Green, insurance companies repersenting Dr. Benjamin J. Mundell are to pay $900,000 and the hospital's insurance carrier another $400,000 to Nancy Lee and Ira Biggar, the parents of Mark Ira Biggar.

The settlement, believed to be one of the highest in this jurisdiction, was reached after five days of testimony by several medical experts who contended that the child's injuries resulted from 14-hour delay between the time Mrs. Biggar arrived at Georgetown and the child's birth.

cOur contention was that the chances of the baby being normal were substantial, had he been delivered immediately after Mrs. Biggar arrived at the hospital," the family's attorneym Jack H. Olender, said yesterday.

"But the chance of the baby being perfect was taken away because of the doctor's delay," Olender said. According to court papers, experts have confirmed that Mark Biggar, who born in July 1975, will suffer permanently from cerebral palsy, a severe defect of the nervous system, and extensive brain damage.

Mundell a private obstetrician on Georgetown's medical staff, "vigorously denied there was any departure from standard of obstetrics" as they existed at the time Mark Biggar was born, according to Mindell's attorney, Francis L. Casey Jr.

Casey said that although his client, Mundell, and the hospital, represented by attorney Thomas P. Jackson, both denied medical malpractice in the case, the insurance companies for both defendants agreed to settle the matter out of court because of "an overwhelming sympathy factor.

"Here we have a child with an IQ of between 20 and 40," Casey said, "who will always be dependent and never will be able to take care of himself."

If the 5-day trial had continued before Judge Green, Casey said, the injury could have been persuaded to make a damaged award large than the settlement.

The Biggars' attorney, Olender, said yesterday that on the evening of July 25, 1975, Nancy Biggar, a registered nurse, telephoned Mundell, her obstetrician, and said she had noticed stains that indicated a problem with her pregnancy. According to Olender, Mundell told Biggar to report to the hospital.

Expert physicians testifying for the family told the jury that Nancy Biggar should have been tested for a womb infection immediately upon her arrival at the hospital. If the womb was found infected-as it eventually was in Biggar's case-then the child should have been delivered immediately by caesarian section to remove it from the "infected environment," the experts said.

According to testimony, Mundell arrived at Georgetown Hospital eight hours later. The child was delivered naturally 14 hours after Biggar arrived at the hospital. Olender contended injury to the child.

Mundell's attorney, Casey, said witnesses were prepared to testify on Mundell's behalf that the child's physical and mental retardation "are due largely to his prematurity, not to medical malpractice.

"This child was born at 33 weeks gestation, apparently in remarkably good health," Casey said. On its second day of life, Casey said the infant was found to be suffering from a condition in which portions of his intestinal walls were dead.

At 4-days-old, Casey said the infant was put under anesthesia for two hours so that surgeons could remove 90 percent of his larfe intestines.

After another period of apparently good helath, Casey said the child-at 10 days old-began to show signs of epilepsy, a disorder of the nervous system that results in seizures. Later, Casey said the infant was also found to have impaired vision.

Witnesses for the Biggars testified that Mark, an only child, will need extensive medical and therapeutic care for the rest of his life-which should be a normal life expectancy, attorney Olender said.

A psychologist testified that the boy, who lived his parents and receives medical treatment outside the home, should have 24-hour care in an institution.

"The experts hold out no hope that the child will ever be trainable," Olender said.