1. Fertility Clinic; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
2. Department of Obstetrics and Gynecology; Institute of Clinical Sciences; Sahlgrenska Academy; University of Gothenburg; Reproductive Medicine; Sahlgrenska University Hospital; Gothenburg Sweden
3. Department of Global Public Health and Primary Health Care; University of Bergen; Bergen Norway
4. Medical Birth Registry of Norway; Norwegian Institute of Public Health; Bergen Norway
5. Department of Obstetrics and Gynecology; University of Helsinki; Helsinki University Hospital; Helsinki Finland
6. Perinatal Center; Department of Obstetrics and Gynecology; Institute of Clinical Sciences; Sahlgrenska Academy; Gothenburg University; Sahlgrenska University Hospital/East; Gothenburg Sweden
7. Spiren Fertility Clinic; Trondheim Norway
8. Central Norway Regional Health Authority; Stjørdal Norway
9. Department of Public Health and General Practice; Norwegian University of Science and Technology; Trondheim Norway
10. National Institute for Health and Welfare (THL); Helsinki Finland
11. Department of Neurobiology, Care Sciences and Society; Division of Family Medicine; Karolinska Institute; Stockholm Sweden
12. Gynecological Clinic; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
13. Section of Biostatistics; Department of Public Health; University of Copenhagen; Copenhagen Denmark
14. Department of Obstetrics and Gynecology; Hvidovre Hospital; University of Copenhagen; Copenhagen Denmark