1. Department of Clinical and Molecular MedicineNorwegian University of Science and Technology Trondheim Norway
2. Department of Obstetrics and GynaecologySt Olavs Hospital, Trondheim University Hospital, Trondheim Norway
3. Department of GynaecologyOslo University Hospital Ullevaal, Oslo Norway
4. Faculty of MedicineUniversity of Oslo Oslo Norway
5. Department of Public Health and NursingNorwegian University of Science and Technology Trondheim Norway