Dr. Helen B. Taussig, 87, one of the two physicians who developed a famous operation to alleviate the "blue baby" syndrome caused by a congenital heart malformation, died May 20 in West Chester, Pa., of injuries suffered in a traffic accident.

Pennsylvania State Police said her car was struck broadside by another automobile as she drove out of the parking lot of the Pennsbury Township Municipal Building after having voted in the state primary elections. She died at Chester County Hospital about an hour after the accident.

An internationally known pediatric cardiologist, Dr. Taussig was the physician in charge of the cardiac clinic of the Harriet Lane Home at Baltimore's Johns Hopkins Hospital from 1930 to 1963. She was the first American physician to investigate and report on birth defects in babies born to women in West Germany who had taken the drug Thalidomide during pregnancy. She was awarded the President's Medal of Freedom, the nation's highest civilian honor, for her work in this area.

Dr. Thomas J. Ryan, president of the American Heart Association, called Dr. Taussig "the founder of pediatric cardiology." In a statement issued through the association's headquarters in Dallas, he said Dr. Taussig's research into congenital heart disease "helped open up a whole new field of medicine."

It was in November 1944 that Dr. Taussig and Dr. Alfred Blalock, a Johns Hopkins surgeon, developed the operation for "blue babies," infants whose skin took on a bluish hue because of a lack of oxygen in the blood. The condition almost always meant a life of severely restricted activity and an early death.

After years of study, Dr. Taussig had developed a theory that a constriction or blockage of the artery connecting the heart to the lungs was the reason for the lack of oxygen in the infants' blood.

The two physicians devised a procedure in which they took a branch of the aorta that normally went to the arm and connected it to the lungs. The first operation was a failure, but the next was successful as were 80 percent of those that followed. As a result, thousands of "blue babies" have led normal or near-normal lives.

The operation, known in the medical community as the "Blalock-Taussig procedure," was developed at a time when there were few, if any, medical remedies for children with congenital heart defects. It proved to be an important steppingstone to other methods of treating those conditions.

With the development of heart-lung machines and the advent of open-heart surgery, Blalock-Taussig is no longer used as frequently as it was during the 10 or 15 years after it was developed. But it remains one of the useful medical options in the treatment of congenital heart defects in children.

It was also in her capacity as a pediatric cardiologist that Dr. Taussig began her investigation into the drug Thalidomide, a sedative that was used widely in West Germany in the late 1950s and early 1960s for its properties of inducing prompt, deep and natural sleep that was not followed by a hangover.

One of her former students at Johns Hopkins told her in 1961 of a high incidence of babies being born with heart defects in West Germany, and he said he suspected it had something to do with a sleeping tablet.

"I decided I'd better to go Germany to find out if it were true or not," Dr. Taussig recalled later. At the same time West German physicians were investigating a high incidence of children being born without arms or legs.

Eventually they discovered that the mothers had taken Thalidomide during pregnancy. Dr. Taussig returned to the United States and reported her findings to medical associations and to the Food and Drug Administration, which had not yet approved the drug for use in this country.

Born in Cambridge, Mass., the daughter of a noted Harvard professor and economist, Frank William Taussig, Dr. Taussig graduated from the University of California and the Johns Hopkins Medical School. She interned at Johns Hopkins Hospital and joined the medical faculty in 1930.

In 1959 she became the first woman to be made a full professor at the Johns Hopkins Medical School and in 1965 she became the first woman to be president of the American Heart Association.

Dr. Taussig retired from teaching and became professor emeritus in 1963. But she continued her research and most recently had been studying heart defects in birds. Colleagues said she continued to work in the laboratories at Johns Hopkins for one or two days a week.

In recent years she had lived in Kennett Square, Pa.

She leaves no immediate survivors.