1. Oslo University Hospital; Section of Obstetrics at the Woman and Children's Division; Oslo University; Oslo Norway
2. National Resource Centre for Women's Health at the Division of Obstetrics and Gynecology; Oslo University Hospital; Oslo Norway
3. Department of Public Health and General Practice at the Faculty of Medicine; The Norwegian University of Science and Technology (NTNU); Trondheim Norway
4. St.Olavs Hospital; Trondheim Norway
5. Department of Health, Nutrition and Management; Faculty of Health Sciences; Oslo Akershus University College of Applied Sciences; Oslo Norway