  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.
