Fetal growth restriction (FGR) is one of the major contributors to adverse perinatal outcome. The purpose of this work was to extend the use of Ultrasound Doppler measurements and allow early and accurate detection of FGR. To this end, a mathematical model was developed to represent the major fetal hemodynamic mechanisms involved. Based on model parameters' values, the forward model predicted flow waveforms at the locations where Doppler measurements are routinely performed. Blood velocity waveforms measured in 20 FGR and 20 normal fetuses were used as inputs to an inverse model solution to obtain the parameters' values of the specific fetus. Model predictions indicated significant changes in the circulation of FGR fetuses compared to normal fetuses. Estimated cardiac output was significantly lower in the FGR group compared to the control group (330±52 ml min-1 Kg-1 compared to 396±52 ml min-1 Kg-1, P<0.001). Also, estimated cardiac output distribution towards the placenta was lower for the FGR group (145±49 ml min-1 Kg-1 compared to 181±31 ml min-1 Kg-1, P<0.01). In the FGR group the model indicated also significant increase in estimated cardiac output distribution towards the brain (9.6±0.7%, compared to 8.0±1.6 %, P<0.01) and in the degree of blood shunted by the ductus venosus (60.6±17.7 %, compared to 39.7±14.8 %, P<0.01), indicating severe brain-sparing state in these fetuses. We conclude that patient-specific mathematical modeling is a promising direction for personalizing and optimizing the treatment options in pregnancies complicated by fetal growth-restriction.