1. Department of Obstetrics and Gynaecology Stavanger University Hospital Stavanger Norway
2. Department of Clinical Science, Medical Faculty University of Bergen Bergen Norway
3. Department of Obstetrics and Gynaecology Trondheim University Hospital (St Olavs Hospital) Trondheim Norway
4. Centre for Fetal Medicine Trondheim University Hospital (St Olavs Hospital) Trondheim Norway
5. Department of Clinical and Molecular Medicine Norwegian University of Science and Technology Trondheim Norway