1. Department of Obstetrics, Women and Children′s Division; Oslo University Hospital Rikshospitalet; Oslo Norway
2. Norwegian National Advisory Unit on Women′s Health; Oslo University Hospital, Rikshospitalet; Oslo Norway
3. Oslo Centre for Biostatistics and Epidemiology; Oslo University Hospital; Oslo Norway
4. University of Oslo; Oslo Norway
5. Department of Transplantation Medicine; Oslo University Hospital, Rikshospitalet; Oslo Norway
6. Research Unit; Sørlandet Hospital; Arendal Norway