Poor health care, low incomes and weak family structures create the learning problems that result in a disproportionately high number of black students being placed in special education classes in Prince Georges's County schools, a George Washington University professor told a federal court today.

Testifying as an expert defense witness for the county school board in the three-week-old school desegregation trial, Rita Ives said that the great influx of black students from the District of Columbia during the 1970s was also a factor.

"These children coming in would require a greater [educational] intensity than the regular classroom can give," Ives told U.S. District Court Judge Frank A. Kaufman. Ives, chairwoman of the special education department at GWU, cited a study commissioned by D.C. Mayor Marion Barry that revealed a high infant mortality rate and poor prenatal care in the city, as well as her personal experience in area schools, to support her assertion.

According to the NAACP, the plaintiff in the lawsuit, grouping large numbers of black children in special education classes is a form of segregation. The NAACP contends that the 116,000-pupil school system, 13th largest in the U.S., never fully implemented a sweeping 1972 desegregation plan ordered by Kaufman.

In 1980, pupils characterized as specific learning disabled (SLD), one category of special education, accounted for most of the county's special education population. That year, blacks made up 49 percent of all county students, but 63.8 percent of SLD students.

Ives strongly disagreed with the NAACP's statistical inference that placement amounts to discrimination.

"We have a more needful number of kids arriving at our doors--why must we pretend that this is not so?" she said. "Another credible way of looking at these statistics is as a measure of the system's responsiveness," she added, praising the Prince George's special education program as one of the 10 best in the country.

"The fact that they are black makes them casualties of society, we have to serve them where they are," Ives said.

Under cross-examination, Ives said that she did not know if blacks in Prince George's generally occupied a lower socioeconomic status than whites. But she said that, even if they were equal, the higher incidence in special education classes might still be justified because current economic stature does not necessarily eliminate health and other problems at the prenatal stage or problems with family structure.

According to Ives, the special education referral process in the county, which requires parental consent and screening by an eight-member panel, is as free from racial bias as possible. She conceded that some teachers tend to refer culturally different children for special education classes but said that, "It is very naive to think that a series of people will not recognize these things and take them into account."

After hearing Ives' testimony and that of George Coombs, director of special education for the county schools, Kaufman told NAACP lawyer Joseph Hassett he did not see any evidence of segregation in the school system's placement of blacks in special education classes.

"When you get all through, we've got some differences of opinion, we've got some statistical variances, but unless you're attacking the good faith of the school system, then at best . . . you have differences of opinion, that's all," the judge said.

In an interview after she testified, Ives added, "We know that nutrition has to do with attention span, which certainly is related to school. We know that developmental delays are related to prenatal care and postnatal care and we know that prenatal delays affect learning. With proper intervention, those children can function to potential."

In Prince George's, she said, that intervention takes the form of one to six hours a day of special instruction, usually outside the regular classroom.