1. Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
2. Department of Gynecology and Obstetrics Sahlgrenska University Hospital Gothenburg Sweden
3. Department of Obstetrics and Gynecology University of Helsinki, Helsinki University Hospital Helsinki Finland
4. Department of Obstetrics and Gynecology, Research Unit of Clinical Medicine University of Oulu and Oulu University Hospital Oulu Finland