1. Department of Paediatrics; Oslo University Hospital; Oslo Norway
2. Institute of Clinical Medicine; University of Oslo; Oslo Norway
3. Department of Medical Microbiology; Vestre Viken Hospital Trust; Drammen Norway
4. Department of Obstetrics and Gynaecology; Akershus University Hospital (AE); Oslo Norway
5. Department for Biostatistics and Epidemiology; Oslo University Hospital; Oslo Norway
6. Hormone Laboratory; Oslo University Hospital; Oslo Norway
7. Division of Epidemiology; Norwegian Institute of Public Health; Oslo Norway