1. Department of Obstetrics and Gynecology; Herlev University Hospital; Herlev Denmark
2. Department for Clinical Medicine; University of Copenhagen; Copenhagen Denmark
3. Section of Social Medicine; Department of Public Health; University of Copenhagen; Copenhagen Denmark
4. Perinatal Epidemiology Research Unit; Aarhus University Hospital; Aarhus Denmark
5. Department of Pediatrics; Aarhus University Hospital; Aarhus Denmark