At the urging of a large contingent of doctors, nurses, hospital administrators and residents, the Arlington County Board voted unanimously yesterday to ask the Health Systems Agency of Northern Virginia (HSA) not to consider closing the maternity ward at Arlington Hospital.

A recommendation that a task force be appointed to study the possible closure of that hospital's obstetrics unit is contained in the Health System's Agency's 837-page draft report, which is being circulated among area officials for comment.

The HSA, a private nonprofit corporation, created by the federal government in 1976, is charged with studying and projecting health care needs in Northern Virginia over the next five years and making recommendations based on those projections.

The agency found that Arlington's maternity ward has less than 2,000 births each year, provides obstetrical care for only 30 per cent of Arlington women and is within 30 minutes driving time of others hospitals.

Because of this, the agency has recommended that it be studied by a task force for possible closing. The agency also recommended that the maternity ward at Potomac Hospital in Prince William County be considered for closing.

However, county officials and hospital personnel told the board that Arlington's maternity ward serves a large population of low income and medically indigent women, many of whom don't speak English and don't have access to transportation to other hospitals.

Hospital administrator John P. Sverha testified tht closure might have a "domino effect" and result in the eventual closing of gynecological and pediatric services. It would also have a negative effect on Arlington's affiliation as a teaching hospital for Georgetown University, he said.

The agency will hold two public hearings in Arlington and Fairfax counties next week to hear testimony from local officials and residents on its plan. Monday's hearing at the Thomas Jefferson Recreation Center in Arlington is expected to focus on the future of Arlington's maternity ward.