1. Department of Obstetrics and Gynecology, Clínica Universidad de Navarra, School of Medicine; University of Navarra; Pamplona Spain
2. Department of Obstetrics and Gynecology; Hospital Universitario Virgen de la Arrixaca; Murcia Spain
3. Department of Obstetrics and Gynecology; Hospital Universitario Cruces; Bilbao Spain