1. Maternal-Fetal Medicine Unit, Department of Obstetrics and Gynecology, Hospital Clínico San José, Santiago, Chile
2. Department of Perinatology, Clínica Redsalud Vitacura, Santiago, Chile
3. Universitat Autònoma de Barcelona, Bellaterra, Spain
4. Department of Ultrasonography, Clínica Indisa, Santiago, Chile
5. Maternal-Fetal Medicine Unit, Department of Obstetrics and Gynecology, Clínica Alemana, Santiago, Chile
6. Maternal Fetal Medicine Unit, Department of Obstetrics, Vall d'Hebron Barcelona Hospital Campus, Universitat Autònoma de Barcelona, Barcelona, Spain