1. Twins Trust Centre for Research and Clinical Excellence, St George's University Hospitals NHS Foundation Trust Blackshaw Road London SW17 0RE UK
2. Vascular Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London Cranmer Terrace London SW17 0RE UK
3. Fetal Medicine Unit, St George's University Hospitals NHS Foundation Trust Blackshaw Road London SW17 0RE UK
4. Department of Obstetrics and Gynecology Koc University, School of Medicine Istanbul Turkey
5. Department of Statistics Middle East Technical University, Facultys of Arts and Sciences Ankara Turkey
6. Neonatal Unit, St George's University Hospitals NHS Foundation Trust Blackshaw Road London SW17 0RE UK