Abnormality of the placental vasculature affects placental thickness
  Our empirical modeling suggests that deformation of placental vascular growth is associated with abnormal placental chorionic surface shape. Altered chorionic surface shape is associated with lowered placental functional efficiency. We hypothesize that placentas with deformed chorionic surface vascular trees and reduced functional efficiency also have irregular vascular arborization that will be reflected in increased variability of placental thickness and a lower mean thickness.   We find that non-centrality of the umbilical cord insertion is strongly and significantly correlated with disk thickness (Spearman's rho=0.128, p=0.002). Deformed shape is strongly and significantly associated with lower overall thickness and higher variability of thickness with beta between -0.173 and -0.254 (p<0.001) . Both lower mean thickness and high variability of thickness are strongly correlated with higher beta (reduced placental efficiency) (p<0.001 and p=0.038 respectively). Greater thickness variability is correlated with higher beta independent of the other placental shape variables p=0.004. 
Michael Yampolsky, Carolyn M. Salafia, Oleksandr Shlakhter, Danielle   Haas, Barbara Eucker, John Thorp
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