Biomechanical modelling of the feto-placental and utero-placental circulations; where to from here?

Biomechanical computational modelling has been used since the 1980s to understand the health of the placenta, and to interpret clinical imaging in pregnancy. In the last few decades, alongside rapid advances in computing power and imaging technologies, biomechanical computational models have been developed that enable researchers to link anatomy to function across temporal and spatial scales. Blood flow through the feto-placental or utero-placental circulations has been a key focus of many of these models, due to the functional importance of these dynamically linked circulations in facilitating exchange of nutrients, oxygen and wastes, and in turn ensuring healthy fetal growth. This review aims to analyse the current state-of-the-art biomechanical models of fetal and maternal blood flow in the placenta, including lumped parameter, computational fluid dynamics, and network models. We consider how different models have been parameterized by data from an array of imaging technologies, from in vivo ultrasound or magnetic resonance imaging, to ex vivo computed tomography and histology data. Building on this, we incorporate learnings from the wider field of cardiovascular biomechanics to suggest future focus areas to further improve the insight gained from computational modelling approaches in pregnancy, and improve future interpretation of diagnostic imaging in this setting.