1. Center for Clinical Epidemiology; Odense University Hospital; Odense Denmark
2. Research Unit of Clinical Epidemiology; Institute of Clinical Research, University of Southern Denmark; Odense Denmark
3. Department of Obstetrics and Gynecology; Herlev University Hospital; Copenhagen Denmark
4. University of Copenhagen; Copenhagen Denmark
5. Hans Christian Andersen Children's Hospital; Odense University Hospital; Odense Denmark
6. Research Unit of Pediatrics; Institute of Clinical Research, University of Southern Denmark; Odense Denmark