1 Department of Obstetrics and Gynaecology, Maastricht University Medical Centre (MUMC) & Cardiology Department, Zuyderland Medisch Centrum Heerlen, Maastricht, The Netherlands.
2 Fetal Medicine Unit, Department of Obstetrics and Gynaecology, St George's University of London, London, UK.
3 Department of Surgery and Cancer, Imperial College London, London, UK.
4 Department of Development and Regeneration, KU Leuven, Leuven, Belgium.