1. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The Methodist Hospital, Houston, Texas
2. The Department of Obstetrics and Gynecology, Hospital Rafael Calderón Guardia, San José, Costa Rica
3. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston, Texas
4. Escuela de Medicina y Ciencias de la Salud, Tecnológico de Monterrey, Monterrey, Nuevo León