From the *OMNI Research Group, Division of Maternal-Fetal Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada; †Ottawa Health Research Institute, Ottawa, Canada; ‡Division of Maternal-Fetal Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada; §Division of Epidemiology, School of Public Health, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey; and ¶McLauphlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, Ottawa, Ontario, Canada.
Received July 17, 2003. Received in revised form October 21, 2003. Accepted November 6, 2003.
Address reprint requests to: Dr. Shi Wu Wen, OMNI Research Group, Department of Obstetrics and Gynecology, The Ottawa Hospital, General Campus, 501 Smyth Road, Box 241, Ottawa, Canada, K1H 8L6; e-mail: [email protected].
The authors thank Joyce Martin for assistance in record linkage and Yan Chen for assistance in data analysis.
