BLOOD-CIRCULATION IN THE FETAL SIDE OF THE HUMAN PLACENTA - A MATHEMATICAL-MODEL TO INVESTIGATE THE EFFECTS INDUCED BY RESISTIVE PATHOLOGIES

Objective: This work introduces a mathematical model describing the fe tal-placental blood circulatory system and its interactions with the r emaining fetal vasculature. The model mimics mainly the in vivo behavi or of the fetal placental circulation, without disregarding the ether areas of the fetal vasculature, which are involved by the regulating m echanism. Methods: Placental blood flows are studied both in the absen ce and the presence of resistive pathologies affecting the fetal side of the human placenta, and the variations in hemodynamics are related to the oxygen uptake by the fetal brain and heart. Vasodilation of cer ebral and cardiac vasculature, as well as vasoconstriction of the othe r vessels, are applied to simulate the adjustments required to guarant ee a constant oxygen release to the fetal brain and heart when placent al resistance to blood flow rises. When this compensation is not suffi cient to ensure no decrease in cerebral and cardiac oxygen displacemen t, the heart rate variability is the second mechanism to reach this ai m. If the disease is so serious that the control systems are unable to re-establish normal conditions, then the modifications of the hemodyn amics are used to investigate the parameters related to the developmen t of the pathology. Results: The charts resulting from the model allow the correlation of the responses of the fetus to the onset of placent al resistive pathologies through the variations of the fluid-dynamic i ndices and of O-2 cerebral and coronary uptake. The theoretical result s match the ones present in the literature. Conclusions: This mathemat ical model could be useful to clinicians when it is very difficult to perform direct analysis or measurements.