The Office of Management and Budget has approved a revised proposal for a major government study to determine whether video display terminals cause miscarriages in female workers, an OMB spokesman said yesterday.

The budget agency last December rejected the original proposal by the National Institute of Occupational Safety and Health (NIOSH), citing research design flaws. It acted after BellSouth, one of the telephone companies whose workers were to be studied, hired scientists from Harvard and Brown universities to look for defects in the NIOSH proposal.

In a letter advising the Department of Health and Human Services, NIOSH's parent agency, of the decision to approve the revised study, James B. MacRae Jr. of OMB's Office of Information and Regulatory Affairs wrote, "We believe that this is an important study." The letter said NIOSH could proceed on condition that it delete some questions from the study questionnaire and obtain medical records to validate reported pregnancy complications.

The study, first announced in 1983, has been awaited by unions, industry officials and health experts because of reports of increased rates of miscarriages, birth defects and other pregnancy complications in some offices where pregnant women used VDTs. About 7 million working women use VDTs.