Affiliation: | 1. Department of Obstetrics and Gynecology, Fetal Medicine Center, Clinica Las Condes, Santiago, Chile;2. Department of Obstetrics and Gynecology, Ultrasound Unit, San Juan de Dios Hospital, University of Chile School of Medicine, Santiago, Chile;3. Department of Obstetrics and Gynecology, San Camilo Hospital, Los Andes, Chile |