1. Department of Obstetrics and Gynecology, Facultad de Medicina, Universidad de Zaragoza, Spain
2. Hospital Clínico de Zaragoza, Zaragoza, Spain
3. Department of Obstetrics and Gynecology, Hospital Torrecárdenas, Almería, Spain
4. High Risk Pregnancy Unit, Enrique C. Sotomayor Obstetrics and Gynecology Hospital, Facultad de Medicina, Universidad Católica de Santiago de Guayaquil, Ecuador