1. Department of Maternal–Fetal Medicine, Hospital Universitari Vall d’Hebron, Universitat Autónoma de Barcelona, Barcelona, Spain;
2. Department of Obstetrics and Gynecology, Hospital Universitario La Paz, Madrid, Spain;
3. Department of Paediatric Radiology, Hospital Universitari Vall d’Hebron, Barcelona, Spain;
4. Department of Pathology, Hospital Universitari Vall d’Hebron, Barcelona, Spain