1. Department of Obstetrics and Gynaecology, Valme University Hospital, Seville, Spain;
2. Department of Obstetrics and Gynaecology, University of Seville, Seville, Spain;
3. Biostatistics Unit, Department of Preventive Medicine and Public Health, University of Seville, Seville, Spain;
4. Harris Birthright Research Centre for Fetal Medicine, King’s College Hospital, London, UK