Fetal growth restriction (FGR) affects 5-10% of all pregnancies and is one of the leading causes of stillbirth. Concerningly, we cannot predict which pregnancies will go on to develop FGR in early pregnancy, at the time the pathophysiology of the disorder is established, and infact we fail to detect more than half of FGR babies prior to delivery. This means that we miss the opportunity to apply best clinical practice to manage these pregnancies, and cannot intervene with potential novel therapeutic approaches in early pregnancy when they may be most effective. The Pregnancy Modelling group at the University of Auckland is integrating novel computational and experimental approaches to create a ‘virtual pregnancy’ in which we can simulate blood flow and oxygen exchange, incorporating dynamic changes in vessel structure and reactivity throughout the materno-fetal circulation throughout gestation. The overall aim of this work is to determine which arteries matter most for adequate delivery of nutrients and oxygen to the baby, and to use this knowledge to improve our ability to predict FGR by focussing on what really matters. In this talk, Dr James will discuss how this work has led them to challenge current dogma that inadequate spiral artery remodelling is the dominant factor influencing the abnormal uterine artery Doppler waveforms and poor placental perfusion in FGR. Rather, their work has highlighted that inadequate outward remodelling of the larger uterine vessels, in particular the radial arteries, may play key roles in the pathogenesis of FGR. Current work to understand how radial artery remodelling is regulated, and the impact of impaired remodelling on placental exchange in FGR, is being used to inform clinical imaging strategies to incorporate radial artery assessment into novel algorithms to predict FGR in early pregnancy.