1. FETALMED—Fetal Imaging Unit, Maternal-Fetal Diagnostic Center, Santiago, Chile
2. DIAGNUS—Prenatal Diagnosis and Teaching Center, Cordoba, Argentina
3. Grupo Medico Alem, Buenos Aires, Argentina
4. Department of Maternal-Fetal Medicine, Palo Alto Medical Foundation, Mountain View, CA, USA
5. FB Diagnostico por Imagenes, Gualeguaychu, Entre Rios, Argentina
6. Moscow Regions Research Institute of Obstetrics and Gynecology, Medical-Genetics Department, Moscow, Russia
7. Center of Reproductive Medicine, Irkutsk, Russia