Affiliation: | 1. Department of Obstetrics and Gynecology, Valme University Hospital, Seville, Spain;2. Department of Obstetrics and Gynecology, Complejo Asistencial Universitario de Gran Canarias, Gran Canarias, Spain;3. Department of Obstetrics and Gynecology, Complejo Asistencial Universitario de Leon (CAULE), Leon, Spain;4. Biostatistics Unit, Department of Preventive Medicine and Public Health, University of Seville, Seville, Spain |