Prevention of respiratory distress Syndrome : effect of antenatal Dexamethasone administration : hospital and follow up studies / Collaborative group on antenatal steroid therapy ; prepared by Research Triangle Institute, University of Wisconsin, University of Manitoba, University of Miami, Northwestern University, University of Tennessee ; sponsored by Division of Lung Diseases, National Heart, Lung and Blood Institute, U.S. Department of Health and Human Services, Public Health Service, National Institute of Health