Centrality of the Umbilical Cord Insertion in a Human Placenta Influences the Placental Efficiency☆

Abstract

Goal: We assess the effect on placental efficiency of the non-centrality of the umbilical cord insertion and on chorionic vascular distribution to determine if cord centrality measurably affects placental function as reflected in birth weight. Materials and Methods:1,225 placentas collected from a prospective cohort had digital photographs of the chorionic plate. Of these, 1023 were term, 44 had velamentous cord insertion and 12 had missing clinical data, leaving N=967 (94.5 %) cases for analysis. Mathematical tools included a dynamical stochastic growth model of placental vasculature, Fourier analysis of radial parameterization of placental perimeters, and relative chorionic vascular density (a measure of "gaps" in the vascular coverage) derived from manual tracings of the fetal chorionic surface images. Bivariate correlations used Pearson's or Spearman's rank correlation as appropriate, with p<0.05 considered significant. Results:The correlation of the standard deviation of the placental radius (a measure of nonroundness of the placenta) with cord displacement was negligible (r=0.01). Empirical simulations of the vascular growth model with cord displacement showed no deviation from a normal round-tooval placental shape for cord displacement of 10 -50% of placental radius. The correlation of the metabolic scaling exponent β with cord displacement measured by Fourier analysis is 0.17 (p < 0.001). Analysis of the chorionic vascular density in traced images shows a high correlation of the © 2009 Elsevier Ltd. All rights reserved.Corresponding author: Michael Yampolsky, PhD Department of Mathematics University of Toronto 40 St. George Street, Toronto, Canada M5S2E4 yampolsky.michael@gmail.com. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptPlacenta. Author manuscript; available in PMC 2010 December 1. Conclusion:Non-central cord insertion has little measurable correlation with placental shape in observed or simulated placentas. However, placentas with a displaced cord show a markedly reduced transport efficiency, reflected in a larger value of β and hence in a smaller birth weight for a given placental weight. Placentas with a non-central cord insertion have a sparser chorionic vascular distribution, as measured by the relative vascular distance. Even if typically a placenta with a noncentral insertion is of a normal round shape, its vasculature is less metabolically effective. These findings demonstrate another method by which altered placental structure may affect the fetal environment, influencing birth weight and potentially c...

Maternal Demographic and Placental Risk Factors in Term Low Birth Weight in Ghana

“…The largest distance from the point of centrality is a high risk factor to term LBW in our population. Our results suggest that such a shift may indeed affect nutrient supply to the fetus, probably from changes in the vascular tree surface area required for nutrient transport to the fetus [23]. However, further research is necessary to establish if this observation is seen in other study populations.…”

“…Previous reports have suggested that a shift in the centrality of the umbilical cord insertion on the chorionic plate reflects the level of vasculature available for nutrient supply [17,23]. Thus, a greater shift leads to a lower level of vascular distribution available for nutrient exchange (and vice versa) [24].…”

“…Interestingly, there was little evidence in our study that vascular tree structure associated with LBW suggesting that the structure may not strongly impact the volume or available surface area for nutrient exchange in the study population. The vascular tree has been suggested to be the sole source of oxygen and nutrient to the fetus, thereby defining placental efficiency [23,24]. Thus, it appears that nutrient delivery to the fetus may be minimally affected if placental efficiency in nutrient delivery is not unduly compromised by the vascular tree morphology.…”

“…Placental factors include changes in placental morphology and insults to the placenta such as infarcts, chronic villous inflammation, and vascular vessel thrombosis. Placental morphological changes include the length, breadth, weight and any shifts from central insertion of the umbilical cord on the chorionic plate to an irregular velamentous insertion [23,24]. Such changes affect the placental efficiency with regards to adequate development of the vasculature to meet the nutrient and oxygen supply to the fetus [25,26].…”

Study of Length of Umbilical Cord and Fetal Outcome: A Study of 1,000 Deliveries

“…There was no difference in the overall mode of delivery for the cord, entangled, or non-entangled and all twins, although cord entanglement was more prevalent in spontaneous vertex vaginal deliveries [8].…”