1. The Fertility Clinic Regional Hospital Horsens Horsens Denmark
2. Department of Obstetrics and Gynaecology Institute of Clinical Medicine Aarhus University Hospital Aarhus Denmark
3. Department of Public Health, Section for Epidemiology Aarhus University Aarhus Denmark
4. Department of Health Science and Technology, Public Health and Epidemiology Group Aalborg University Aalborg Denmark
5. Department of Obstetrics and Gynaecology Herlev and Gentofte Hospital Herlev Denmark
6. Institute of Clinical Medicine University of Copenhagen Copenhagen Denmark