1. South Australian Health and Medical Research Institute; Adelaide SA Australia
2. School of Public Health; The University of Adelaide; Adelaide SA Australia
3. Julius Center for Health Sciences and Primary Care; University Medical Center Utrecht; Utrecht the Netherlands
4. Women's Health Research Unit; Barts and the London School of Medicine and Dentistry; Queen Mary University of London; London UK
5. CIBER Epidemiology and Public Health and IRYCIS; Madrid Spain
6. Robinson Research Institute; School of Medicine; The University of Adelaide; Adelaide SA Australia
7. Department of Obstetrics & Gynecology and GROW-School for Oncology and Developmental Biology; Maastricht University Medical Centre; Maastricht the Netherlands
8. Department of Obstetrics and Gynecology; American University of Beirut Medical Center; Beirut Lebanon
9. Department of Obstetrics; Rigshospitalet; Copenhagen University Hospital; Copenhagen Denmark
10. Department of Clinical Biochemistry; Herlev and Gentofte Hospital; Copenhagen University Hospital; Copenhagen Denmark
11. Maternal-Fetal Medicine Unit; Valencia Infertility Institute; University of Valencia; Valencia Spain
12. George Washington University Biostatistics Center; Washington DC USA
13. Department of Obstetrics and Gynecology; Paule de Viguier Hospital; CHU Toulouse; Toulouse France
14. UMR 1027 INSERM; University of Paul Sabatier Toulouse III; Toulouse France
15. Department of Obstetrics and Gynaecology; Monash Medical Centre; Monash Health and Monash University; Clayton Vic. Australia
16. Warwick Clinical Trials Unit; University of Warwick; Coventry UK