1. Department of Obstetrics and Gynaecology; Stavanger University Hospital; Stavanger Norway
2. Department of Obstetrics and Gynaecology; University Hospital of North Norway; Tromsø Norway
3. Women's Health and Perinatology Research Group; Department of Clinical Medicine; University of Tromsø; Tromsø Norway
4. National Center for Fetal Medicine; Trondheim University Hospital; Trondheim Norway
5. Division of Immunology and Transfusion Medicine; Department of Laboratory Medicine; University Hospital of North Norway; Tromsø Norway
6. Department of Health Studies; University of Stavanger; Stavanger Norway