1 Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
2 Fetal Medicine Unit, St George's University Hospitals NHS Foundation Trust and Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK.
3 School of Clinical Sciences, University of Nottingham, Division of Obstetrics and Gynaecology, Maternity Department, City Hospital, Nottingham, UK.
4 UCL Elizabeth Garrett Anderson Institute for Women's Health, University College London, London, UK.
5 Unit of Fetal Medicine and Prenatal Diagnosis, Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy.
6 Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.
7 Fetal Medicine Unit, University College London Hospitals NHS Foundation Trust, London, UK.
8 Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, Imperial College NHS Trust, London, UK.