1. Perinatal Epidemiology Research Unit, Departments of Obstetrics and Gynaecology and Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada; Departments of
2. Pathology
3. Obstetrics and Gynaecology
4. Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
5. University of Ottawa and the Ottawa Hospital, Ottawa, Ontario, Canada