John Simpson is Professor of Paediatric and Fetal Cardiology at the Evelina London Children’s Hospital, Guy’s and St Thomas NHS Foundation Trust. He qualified in medicine from the University of Edinburgh and trained in paediatric cardiology at Guy’s Hospital, London and the University of California, San Francisco. Professor Simpson has published over 300 peer-reviewed papers in the field and is a co-author of UK, US and European guidelines on the practice of fetal echocardiography and fetal cardiology. He is past President of the British Congenital Cardiac Association (2019-2021). Vita Zidere is Consultant in Paediatric and Fetal Cardiology at Evelina London Children’s Hospital, Guy’s and St Thomas NHS Foundation Trust. She qualified in medicine from the Riga Stradins University in 1994 and trained in paediatric and fetal cardiology at the University Children’s Hospital in Riga, Latvia, at Guy’s Hospital, London and at Columbia-Presbyterian Medical Centre, Babies Hospital, New York, USA. Dr Zidere has published peer-reviewed papers with a major focus on prenatal diagnosis of congenital heart disease. Owen Miller is a Consultant in Paediatric and Fetal Cardiology and Deputy Medical Director, Evelina London Children’s Hospital. He graduated from the University of Newcastle, Australia and trained in Paediatrics, Paediatric Intensive Care and Paediatric Cardiology in Sydney, Zurich and London. Dr Miller is on the Associate Editor of European Heart Journal - Cardiovascular Imaging and his main clinical and research interests cover advanced cardiac imaging in fetal and paediatric cardiology. Trisha Vigneswaran is the clinical lead for the Evelina London fetal cardiology network and consultant in paediatric and fetal cardiology at the Evelina London Children’s Hospital, Guy’s and St Thomas’ NHS Foundation Trust . She qualified from Imperial College, London in 2003 and undertook specialist training in paediatrics at Bart’s and The London Hospital and subsequently in paediatric and fetal cardiology at Great Ormond Street Hospital, Evelina London Children’s Hospital and King’s College Hospital. Dr Vigneswaran is a co-author of the UK guidelines on the practice of fetal cardiology. In addition to clinical work she also undertakes research in fetal cardiology, having published over 50 peer-reviewed papers with current focus on acute maternal hyperoxygenation testing.