Novel 3D light microscopic analysis of IUGR placentas points to a morphological correlate of compensated ischemic placental disease in humans.

The villous tree of the human placenta is a complex three-dimensional (3D) structure with branches and nodes at the feto-maternal border in the key area of gas and nutrient exchange. Recently we introduced a novel, computer-assisted 3D light microscopic method that enables 3D topological analysis of branching patterns of the human placental villous tree. In the present study we applied this novel method to the 3D architecture of peripheral villous trees of placentas from patients with intrauterine growth retardation (IUGR placentas), a severe obstetric syndrome. We found that the mean branching angle of branches in terminal positions of the villous trees was significantly different statistically between IUGR placentas and clinically normal placentas. Furthermore, the mean tortuosity of branches of villous trees in directly preterminal positions was significantly different statistically between IUGR placentas and clinically normal placentas. We show that these differences can be interpreted as consequences of morphological adaptation of villous trees between IUGR placentas and clinically normal placentas, and may have important consequences for the understanding of the morphological correlates of the efficiency of the placental villous tree and their influence on fetal development.