Blood Flow and Oxygen Transport in the Human Placenta

Background/Purpose: The placenta is a complex organ that performs an extremely important role: nourishing a developing baby. However, possibilities of research into placental complications are scarce, mainly because of the ethical limitations associated with the in-vivo organ and the problematic extrapolation of animal models. This ongoing project aims to shed light on the complex hemodynamics and structural characteristics of placental complications by combining emerging techniques such as, image analysis and patient-specific modeling.

Methods: Undamaged and clot-free lobules were fixed by perfusion. The feto-placental vessels and villous membrane were immunostained and scanned using a confocal laser scanning microscope. The three-dimensional geometries of the terminal villi and its capillary bed were reconstructed and converted into computational models. Oxygen transport between the maternal and fetal blood was modeled using COMSOL Multiphysics.

Results: Models of the feto-placental circulation show that the oxygen flux within a villus is almost constant however, the oxygen saturation of the blood leaving the capillaries varied with an average of 72%. These results are in good agreement with the experimentally measured umbilical vein oxygen saturation, reported to be approximately 80%.

Conclusion: Since most of the models showed an oxygen saturation below 80%, it is reasonable to assume that fetal blood travels through several terminal villi in order to fully saturate the blood. This work highlights the importance of the complex capillary network geometry on the efficiency of placental oxygen transport. The techniques developed in this work have the potential to enlighten on the development of placental derived complications.