1. Fetal Medicine Unit; St George's University Hospitals NHS Foundation Trust; London UK
2. Ankara University Faculty of Medicine; Department of Obstetrics and Gynecology; Ankara Turkey
3. Middle East Technical University; Department of Statistics; Ankara Turkey
4. Molecular & Clinical Sciences Research Institute; St George's University of London; London UK
5. Department of Obstetrics and Gynaecology; Monash University and Monash Ultrasound for Women, Melbourne; Victoria Australia