1. Fetal Medicine Unit, Department of Obstetrics and Gynecology; Hospital General Universitario Gregorio Marañón; Calle O'Donnell, 48, Planta 0, Bloque C; 28009; Madrid; Spain
2. Department of Radiology; Hospital General Gregorio Marañón, Universidad Complutense de Madrid; Spain
3. Department of Pathology; Hospital General Gregorio Marañón, Universidad Complutense de Madrid; Spain