1. Department of Anesthesiology, Department of Obstetrics and Gynecology Washington University School of Medicine St. Louis Missouri USA
2. Section of Epidemiology, Department of Public Health University of Copenhagen Copenhagen Denmark
3. Department of Anesthesiology Washington University School of Medicine St. Louis Missouri USA
4. Child and Adolescent Mental Health Centre – Research Unit, Department of Psychiatry, Capital Region of Denmark, Section of Epidemiology, Department of Public Health University of Copenhagen Copenhagen Denmark