A study of whether to close Arlington Hospital's obstetrics unit, the subject of heated community debate last fall, will be delayed until at least 1980 by the Health Systems Agency of Northern Virginia (HSA).

HSA officials said the study would be delayed because of community concerns about the proposal.

In an 800-page draft of a regional health plan released last fall, the HSA recommended that the obstetrics units at Arlington Hospital and Potomac Hospital in Prince William County be studied for possible closing because of the low number of births at both units. The HSA is one of several hundred private agencies created by the federal government and charged with regional long-ranged health planning.

The HSA draft cited two reasons that the Arlington facility should be considered for closing: Only 30 per cent of Arlington births are at the hospital and there are other facilities within a half hour's drive of Arlington County and surrounding areas.

However, the Arlington medical community mounted a concerted attack of many aspects of the plan, particularly the proposal dealing with the obstetrics unit. The primary criticism was that the plan would sacrifice the quality of health care to a concern over stemming rising costs.

At public hearings last fall, physicians and hospital administrators argued that the unit should remain open since it serves an increasingly large population of indigent, non-English speaking women without easy access to transportation, and thus without easy access to other facilities.

George Barker, assistant HSA director, said the two-year deferral will give Arlington officials time to encourage more patients and physicians to use the hospital. "There are still a lot of things that need to be studied based on the concerns expressed by hospital officials and citizens," he said.

John Sverha, hospital administrator and a vocal opponent of any move that might lead to closing the unit, said, "We're pleased that they seem to be going about it on a reasonable basis rather than first reaching a conclusion. The (obstetrics) unit is already here . . . there needs to be a careful study before they make a rash decision."

Dr. Thomas A. McGavin, head of the obstetrics unit said, "The feeling about Arlington Hospital is that it will never (be closed) as long as there's as much citizen concern about maintaining the unit."