Computational modeling of a human placentone: Simulating uteroplacental hemodynamics

During pregnancy, fetal growth depends on the efficient performance of the placenta. While in vivo measurements of the pregnant uterus are limited due to accessibility and safety concerns, computational modeling offers a tool for gaining valuable insights into healthy and complicated pregnancies. In this study, we present a computational model of the human placentone, the basic functional unit of the placenta. The model consists of maternal vasculature supplying (spiral artery) and draining (decidual veins) the placentone and the lobule, characterized by a villi-containing region and a free-of-villi region proximal to the arterial opening. To explore how uncertainties in placentone anatomy impact uteroplacental blood flow and intervillous space circulation, we systematically examine the sensitivity of key hemodynamic metrics to different placentone model parameters. These parameters include the location and diameter of the decidual veins, the size of the free-of-villi region at the spiral artery opening, and the extent of spiral artery remodeling. For our analysis, we consider arterial entry jet velocity and length, along with intervillous space pressure, as the hemodynamic metrics of interest. We define reference values for these metrics based on available experimental and clinical data on healthy pregnancies. Based on our simulation results, we identify the conditions that lead to a healthy and efficient placentone. We also model pathological cases representative of intrauterine fetal growth restriction and preeclampsia and quantify hemodynamic differences. Our results predict that in pathological cases, maternal blood enters the placentone with higher momentum than in the healthy case, potentially damaging the delicate placental villi.