1. Department of Obstetrics; Rigshospitalet Copenhagen University Hospital; Copenhagen Denmark
2. Department of Obstetrics and Gynecology; Holbaek University Hospital; Holbaek Denmark
3. Department of Global Public Health and Primary Care; University of Bergen; Bergen Norway
4. Medical Birth Register of Norway; Norwegian Institute of Public Health; Bergen Norway
5. Department of Obstetrics and Gynecology; University of Helsinki; Helsinki University Central Hospital; Helsinki Finland
6. Department of Gynecology and Pediatrics; University of Helsinki; Helsinki University Central Hospital; Helsinki Finland
7. Department of Gynecology and Obstetrics; Hyvinkää Hospital; Helsinki Finland
8. THL National Institute for Health and Welfare; Helsinki Finland
9. Department of Neurobiology, Care Sciences and Society; Division of Family Medicine; Karolinska Institute; Stockholm Sweden
10. Department of Clinical Science Intervention and Technology (CLINTEC); Karolinska Institute and Department of Gynecology and Obstetrics; Karolinska University Hospital; Stockholm Sweden
11. Department of Evaluation and Analysis; Epidemiology and Methodological Support Unit; National Board of Health and Welfare; Stockholm Sweden
12. Department of Obstetrics and Gynecology; Institution of Clinical Sciences; University of Lund; Lund Sweden
13. Department of Obstetrics and Gynecology; Haukeland University Hospital; Bergen Norway
14. Department of Clinical Science; University of Bergen; Bergen Norway
15. Department of Obstetrics and Gynecology; Landspitali University Hospital; Reykjavik Iceland