1. Department of Obstetrics and Gynecology; University of Oulu; Oulu Finland
2. Department of Anesthesiology and Surgery; Oulu University Hospital; Oulu Finland
3. Division of Operative Care and Medical Research Center Oulu; Oulu University Hospital and University of Oulu; Finland
4. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology; Oregon Health & Science University; Portland OR USA
5. Women's Health and Perinatology Research Group, Department of Clinical Medicine, Faculty of Health Science; University of Norway and University Hospital of Northern Norway; Tromsø Norway
6. Department of Clinical Science, Intervention and Technology; Karolinska Institute; Stockholm Sweden
7. Department of Obstetrics and Gynecology; Helsinki University Hospital; Helsinki Finland