1. Department of Obstetrics and Gynecology; Helse Stavanger; Stavanger Norway
2. National Centre for Ultrasound in Gastroenterology; Haukeland University Hospital; Bergen Norway
3. Department of Clinical Medicine; University of Bergen; Bergen Norway
4. Department of Obstetrics and Gynecology; Haukeland University Hospital; Bergen Norway
5. Department of Clinical Science; University of Bergen; Bergen Norway
6. Centre for Clinical Research; Haukeland University Hospital; Bergen Norway
7. Department of Global Public Health and Primary Care; University of Bergen; Bergen Norway