Between 1973 and 1976, the disparity between black and white infant mortality rates in the District of Columbia had increased to the point where black infants are now more than 3.5 times as likely to die before their first birthday as are white infants, accoring to newly compiled city government statistics.

The new figures show a white infant mortality rate of 7.5 death per 1,000 live births, a figure better than that in Sweden, which with eight deaths per 1,000 has the lowest rate in the world.

The black infant death rate in the District, however, is 27.7 per 1,000, only about one death per 1,000 worse than the U.S. national average for blacks, but placing Washington blacks behind citizens of such contries as Taiwan, which has an annual per capita income of only $890.

The difference between the black and white neonatal death rate - the rate for infants between birth and 28 days - was even more marked; 27 black deaths per 1,000 verses 37 white deaths.

This compares to a rate in 1973 of 19.7 black deaths per 1,000 live births and 16.2 white deaths per 1,000. The infant mortality rate four years ago was 26 per 1,000 live births for black and 21.8 for whites.

"The really striking thing is not that the black rates have gotten terrible, it's that the whites have gotten strikingly better and the blacks haven't participated" in the improvement, said Dr. Gordon Avery, chief of neonatology at Childrens Hospital National Medical Center.

The new statistics do represent a marked improvement in the city's overall infant mortality rate over 1975, when the rate for both white and black infants was 28.6 per 1,000. In 1976, the overall rate declined to 24.9 per thousand.

City officials contacted yesterday focused on this decline in the city's overall infant mortality rate than on the fact the rate continues to be extreme high, or on the increasing disparity between the rates for blacks and whites.

Department of Human Resources director Albert Russo, responding to an inquiry made to Mayor Walter Washington, said that "on behalf of the mayor, we are encouraged by the fact that . . . during calender year 1976, we experienced a drop of 13 per cent in the rate of infant mortality over calender 1975 . . .

"We continue to be quite concerned and quite sensitive about the high rate of infant mortality . . . We are vigorously addressing this grave matter," said Russo, as Washington's spokesman Sam Eastman and Health and Hospitals Administration director Dr. Raymond Standard listened in.

"Infant mortality for blacks today is higher in the U.S. than it was for whites 25 years ago," said Standard, when asked about the racial disparity. "You need to look at the plight and problems of blacks nationwide."

Standard and several other physicians interviewed yesterday pointed out that the impression left by the figures may be skewed by the fact that there were so few white infant deaths in the city - only 10 on 1976.

Because the numbers are so low, a change of five deaths more or less can cause a marked change it, the statistics, a change that would have little meaning in terms of the picture of health care.

Standard defended the current city administration, saying that "we have adequate services available." The DHR clinics provide "excellent prenatal carer." he said. "You have to look at motivation. It's not the lack of service, it's a lack of motivation" on the part of poor women who he said do not use the service available.

One of the things that is particularly surprising about the high infant mortality rate in the city if that there are six neonatal intensive care units in Washington hospitals, three of which are among the best in the city "has just been granted a federal grant for improved pregnancy outcome." Part of the $600,000 will go, he said, "to outreach and providing special services for high-risk patients. We are going to be able to make a more intensive effort to take care of high-risk mothers," he said.

The large number of women among the city's black population whose pregnancies are considered high-risk is one explanation of the high black infant and neonatal mortailities rates.

About 24 per cent of all births in the city in 1976 were to adolescent those most likely to run into complications affecting their health and the heath of their babies.

Dr. Frederick Green, assosciate director of Children's Hospital, repeatedly stressed the factor of teenage pregnancy when asked about the high infant mortality rates.

Teen-agers, said Green, are even loss likely than slightly older poor to avail themselves of the prenatal services available in the city.

One of the roblems, said Avery, is that "the idea of supportive health care when you're not acutely ill (such as during pregnancy) is somethings middle class people think about and a hospital is somewhere you go if you're deathly ill, if you're poor and suspicious. So a lot of (poor) women walk in already in labor with their hypertension and their diabetes."

Mary Kate Davit, director of the nurseries at Georgetown University Medical Center, said the new statistics "over all suggest" that the health care being recieved by poor black mothers is "lousy . . . I would say there's a prenatal factor involved, but when you look at the infant death rate, the neonatal death rate, you just wonder what kind of perinatal care, during labor, delivery and after, these babies are getting."

Davit said the "most obvious discrepancy between the white and black babies "is socioeconomic. We know that nutrition is probably worse" for the blacks. "We know that prinatal care is spotty . . . Whether it's because they don't seek the care out of ignorance or it's difficult for them to get to or both. I don't know. I suspect it's both," she said.