1. Department of Obstetrics and Gynaecology University of Cairo Cairo Egypt
2. Division of Maternal–Fetal Medicine, Department of Obstetrics and Gynecology Baylor College of Medicine Houston Texas USA
3. Fetal Medicine Unit, Department of Obstetrics and Gynaecology St George's Hospital London UK
4. EGA Institute for Women's Health, Faculty of Population Health Sciences University College London (UCL) London UK