The District of Columbia, which has one of the highest infant mortality rates in the country, could save both lives and money by aggressively promoting good health care for pregnant women rather than focusing on newborn children, according to a study released by the Greater Washington Research Center.

The report's recommendation on preventive care runs counter to the position taken three years ago by the District's Blue Ribbon Commission on Infant Mortality, which recommended that the city concentrate on improving hospital care for newborn infants.

Some of the blue ribbon commission's recommendations have been implemented with some success, the report said, but compared with other localities the city's infant death rate remains high, particularly in the black community.

The research center's report suggests, in essence, that the benefits to be gained by concentrating on infant care have already been realized and that the most profitable avenue now would be to concentrate on preventive care.

The overall 1981 infant mortality rate in the District was 22.6 deaths per 1,000 live births. The black infant mortality rate, however, was 25.5 compared to 14.1 for whites. According to the most recent comparable figures available, the District's infant mortality rate in 1978 was 26.6 deaths per 1,000 live births compared to a national average of 14.4.

The report released yesterday stresses the high correlation between very low birth weights, usually a result of premature births, and high infant mortality.

According to Dr. LaSalle D. Leffall Jr., vice chairman of the research center and chairman of the department of surgery at Howard University Hospital, an infant of normal birth weight in the District -- five and one-half pounds or more -- has less than a 1 percent chance of dying in its first year. An infant weighing between 3.3 and 5.5 pounds has a 3 percent chance of dying.

But an infant of very low birth weight -- under 3.3 pounds -- has almost a 50 percent chance of dying in its first year.

About 2.7 percent of the black children born in the District weighed under 3.3 pounds. That percentage of infants with very low birth weight is 14 percent higher than the national black average and three times the national white average, according to the report.

"Most seriously underweight infants born to District residents appear to be born to poor black women," Leffall said yesterday. "While prenatal medical care and nutritional supplementation services are available in the city, for a variety of reasons some poor black women do not take advantage of these services.

"They also do not get adequate warning that some of their personal habits, such as smoking and use of alcohol, are of potential harm to their unborn children."

Therefore, Leffall said, the task force that drafted the report recommends an "aggressive" program, "targeted to specific geographic areas of the District whose residents have a high incidence of prematurity." Two such areas cited were Southeast Washington and Anacostia.

Leffall cited estimates showing that the District now spends roughly $20 million a year caring in one way or another for very low birth weight babies who survive. Improving the prenatal health habits of the mothers of these infants could produce dramatic savings, Leffall said.

The report recommends appointment of a single, full-time official in the mayor's office to "lead and coordinate a city-wide preventive program." The report called for a three-year pilot effort, to cost an estimated $100,000 annually, employing persons from the community to make contact with pregnant women to inform them about good prenatal health practices and about services and clinics available to them.

The task force also recommended that hospitals in the metropolitan area establish a system of measuring the sophistication of their infant care facilities and arranging for the transfer of high risk mothers and infants "to appropriate highly sophisticated facilities."

Dr. Lennox Westney, director of obstetrics at Howard University Hospital and a member of the Blue Ribbon Commission, said he had not seen the research center's report but agreed with the recommendations as they were described to him.