1. Department of Obstetrics and Gynaecology; VU University Medical Centre Amsterdam; Amsterdam The Netherlands
2. Julius Centre for Health Sciences and Primary Care; University Medical Centre Utrecht; Utrecht The Netherlands
3. Department of Obstetrics and Gynaecology; Academic Medical Centre, Amsterdam; The Netherlands
4. Stanford Prevention Research Center; Stanford University; Stanford CA USA
5. Department of Obstetrics and Gynaecology; Onze Lieve Vrouwe Gasthuis; Amsterdam The Netherlands
6. Department of Obstetrics and Gynaecology; Maastricht University Medical Centre; Maastricht The Netherlands
7. Department of Obstetrics and Gynaecology; University Medical Centre Groningen; Groningen The Netherlands
8. Department of Obstetrics and Gynaecology; Maxima Medical Centre, Veldhoven; The Netherlands
9. Department of Obstetrics and Gynaecology; University Medical Centre Utrecht; Utrecht The Netherlands
10. Department of Obstetrics and Gynaecology; Leiden University Medical Centre; Leiden The Netherlands
11. Department of Obstetrics and Gynaecology; Erasmus Medical Centre, Rotterdam; The Netherlands
12. Department of Obstetrics and Gynaecology; Radboud University Medical Centre, Nijmegen; The Netherlands
13. Department of Obstetrics and Gynaecology; Zorggroep Twente, Almelo; The Netherlands
14. Department of Obstetrics and Gynaecology; Isala Clinics Zwolle; Zwolle The Netherlands
15. The Robinson Institute, School of Reproductive Health and Paediatrics; University of Adelaide; Adelaide Australia