1. Department of Women's and Children's HealthKarolinska Institute and Karolinska University Hospital Stockholm Sweden
2. Oulu University HospitalDepartment of Children and Adolescents, and University of OuluPEDEGO Research Unit Oulu Finland
3. Department of Hematology and OncologyUniversity of Tartu Tartu Estonia
4. Children's Hospitalaffiliation of Vilnius University Hospital Santaros Klinikos and Vilnius University Vilnius Lithuania
5. Department of Pediatric Hematology/OncologyOslo University Hospital Oslo Norway
6. Department of Women's and Children's HealthKarolinska Institute Stockholm Sweden
7. Department of PediatricsUniversity of Iceland Reykjavík Iceland
8. Department of Pediatrics and Adolescent MedicineUniversity Hospital RigshospitaletCopenhagen, and Institute of Clinical MedicineFaculty of MedicineUniversity of Copenhagen Denmark
9. Department of Pediatric Hematology‐Oncology and Stem Cell Transplantation, Children's HospitalUniversity of Helsinki and Helsinki University Hospital Helsinki Finland
10. Department of Women's and Children's HealthUniversity of Uppsala Uppsala Sweden