1. Division of Obstetrics and Gynecology, Department of Obstetrics Oslo University Hospital Oslo Norway
2. Norwegian Research Center for Women's Health Oslo University Hospital Oslo Norway
3. Research Unit Sørlandet Hospital HF Kristiansand Norway
4. Institute of Clinical Medicine, Faculty of Medicine University of Oslo Oslo Norway
5. Department of Obstetrics and Gynecology Sørlandet Hospital Arendal Arendal Norway
6. K.G. Jebsen Center for Genetic Epidemiology, Department of Public Health and Nursing Norwegian University of Science and Technology Trondheim Norway
7. Department of Endocrinology, Clinic of Medicine St. Olav's Hospital, Trondheim University Hospital Trondheim Norway
8. Oslo Center of Biostatistics and Epidemiology, Research Support Services Oslo University Hospital Oslo Norway
9. Faculty of Health Sciences Oslo Metropolitan University Oslo Norway