Dr. Carl Swan Shultz, 52, an assistant surgeon general of the United States who played a major role in developing federal policy on family planning, died of multiple myeloma yesterday at National Naval Medical Center in Bethesda.

Dr. Shultz was the current director of the Office of Population Affairs in the Department of Health, Education and Welfare. Early in the first Nixon administration, he helped draft the presidential message that led eventually to passage of the Family Planning and Population Research Act of 1970.

The legislation set up the office that Dr. Shultz eventually headed.

Earlier this year, HEW Secretary Joseph A. Califano awarded Dr. Shultz the department's distinguished Service Medal.It was given, according to the citation, for "sustained and distinguished service as a psysician, child-health education, and pioneer leadership for the establishment of federally supported family planning and population research programs."

Apart from his professional duties, Dr. Shultz was a vice president and member of the board of trustees of the Opera Society of Washington.

According to colleagues in the family planning field, Dr. Shultz, a career officer in the Public Health Service, was a master not only of the medical aspects of his speciatly, but also of administration.

With Dr. Louis Hellman, the first head of the Office of Population Affairs, Dr. Shultz helped implement the 1970 family planning law while avoiding "impasses" within the bureaucracy.

The act directed that HEW provide family-planning services to couples in the United States. In 1970, a total of 1.9 million patients were served. The number is expected to be about 4.6 million patients in the current year. The current budget for the Office of Population Affairs is $130 million.

In addition to serving patients, the program funds and directs research on contraception, reproductive biology, and what President Nixon called "the sociology of population growth."

The office also has the legal responsibility for the testing by the Food and Drug Administration of the safety and efficacy of birth-control devices and methods.

Dr. Shultz was born in Los Angeles and attended Pomona College. He received a medical degree from Johns Hopkins University in Baltimore in 1948, and joined the Public Health Service in the early 1950s.

He served in Europe as a quarantine officer and supervisor of medical programs for refugees from 1952 to 1955. He did similar work in Hong Kong from 1955 to 1957.

In 1959 and 1960, he attended the Harvard University School of Public Health, where he earned a master's degree. He then became chief of the school health section in the Public Health Service, a position he held until 1967. He formally began his work in family planning in 1966.

Since 1974, Dr. Shultz had been president of the American Association of Sex Educators, Counselors, and Therapists.

Survivors include his wife, Anne, of the home in Washington; a daughter, Anne Marina, of Washington, and a son, John Peter, of Washington, and a sister, Lorraine Alexander, of Los Angeles.