1. Department of Women's and Children's Health Uppsala University Uppsala Sweden
2. Department of Obstetrics and Gynaecology St Olav's Hospital Trondheim University Hospital Trondheim Norway
3. Department of Laboratory Medicine, Children's and Women's Health Norwegian University of Science and Technology Trondheim Norway
4. Department of Medicine, Solna Clinical Epidemiology Unit Karolinska Institute Stockholm Sweden
5. Department of Women's and Children's Health Karolinska Institute Stockholm Sweden