1. Department of Obstetrics and Gynecology; Noordwest Ziekenhuis; Den Helder the Netherlands
2. Isala Fertility Center, Isala; Zwolle the Netherlands
3. Department of Obstetrics and Gynecology; Amphia Hospital; Breda the Netherlands
4. Department of Obstetrics and Gynecology; Meander Medical Center; Amersfoort the Netherlands
5. Department for Reproductive Medicine; University Medical Center; Utrecht the Netherlands
6. Department of Obstetrics and Gynecology; Jeroen Bosch Hospital‘s; Hertogenbosch the Netherlands
7. Department of Obstetrics and Gynecology; Albert Schweitzer Hospital; Zwijndrecht the Netherlands
8. Department of Obstetrics and Gynecology; University Medical Center Nijmegen; Nijmegen the Netherlands
9. Center for Reproductive Medicine; Academic Medical Center; University of Amsterdam; Amsterdam the Netherlands
10. Department of Obstetrics and Gynecology; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
11. Department of Obstetrics and Gynecology; Medisch Spectrum Twente; Enschede the Netherlands
12. Department of Obstetrics and Gynecology; Onze Lieve Vrouwe Gasthuis; Amsterdam the Netherlands
13. Department of Obstetrics and Gynecology; Máxima Medical Center; Veldhoven the Netherlands
14. Department of Obstetrics and Gynecology; Erasmus Medical Center Rotterdam; Rotterdam the Netherlands
15. Department of Obstetrics and Gynecology; Deventer Hospital; Deventer the Netherlands
16. Department of Obstetrics and Gynecology; Diakonessenhuis; Utrecht the Netherlands
17. Department of Obstetrics and Gynecology; Catharina Hospital; Eindhoven the Netherlands
18. Department of Obstetrics and Gynecology; Medisch Centrum Leeuwarden; Leeuwarden the Netherlands
19. London Women's Clinic; London UK
20. Department of Obstetrics and Gynecology; University Hospital Zealand; Roskilde Denmark