1. Department of Cancer Research and Molecular Medicine; the Norwegian University of Science and Technology; Trondheim; Norway
2. Department of Obstetrics and Gynecology; St. Olavs University Hospital; Trondheim; Norway
3. Department of Obstetrics and Gynecology; Stavanger University Hospital; Stavanger; Norway
4. Department of Obstetrics and Gynecology; Haukeland University Hospital; Bergen; Norway