1. Department of Obstetrics and Gynecology Valme University Hospital Seville Spain
2. Department of Obstetrics and Gynecology, Faculty of Medicine University of Seville Seville Spain
3. Department of Obstetrics and Gynecology University Healthcare Complex of Gran Canaria Gran Canaria Spain
4. Department of Obstetrics and Gynecology University Healthcare Complex of Leon (CAULE) Leon Spain
5. Department of Obstetrics and Gynecology Virgen de la Victoria University Hospital of Malaga Malaga Spain
6. Biostatistics Unit, Department of Preventive Medicine and Public Health University of Seville Seville Spain
7. Department of Obstetrics and Gynecology Juan Ramón Jimenez Hospital Seville Spain