The Diameter Distribution of the Stem Villi Arteries Does Not Discriminate between Normal and Intra Uterine Growth Restricted Placentas

C Guiot,G Kosanke,P G Piantà,A Sciarrone,P Kaufmann,T Todros

doi:10.1080/01445349908833025

Abstract

The distribution of the stem villi arteries and arterioles diameter was evaluated on histological sections from 6 normal (control) and 8 Intrauterine Growth Restricted (IUGR) placentas. No significant difference between the diameter distributions was found. This result can be due either to a similar pattern in vascularization or to the inadequacy of the diameter distribution in showing existing differences. Further investigation is needed to make a distinction between these two hypotheses. A multiparametric model is proposed, which predicts the diameter distribution that is expected when a few parameters (describing the vessel geometry and the tree branching structure) are varied in their normal range. The diameter distribution is shown to slightly change or not to change at all when important parameters, such as the vessel asymmetry, are changed. We conclude thatthe diameter distribution is insensitive to variation in certain placental structural parameters. A reliable analysis of the stem villi vasculature in normal and TUGR placentas cannot be based on the comparison of the respective diameter distributions alone.

Highlights

Intrauterine growth restriction (IUGR) with impeded flow in the umbilical arteries is one of the major clinical problems in pregnancy (Kingdom, Rodeck and Kaufmann, 1997)
The eight placentas meeting these criteria were divided into two subgroups on the basis of the umbilical Doppler findings: in 4 cases the value was above the 90th centile with presence of end diastolic velocities (PED); in the other 4 cases there was absence of end diastolic velocities (AED)
The arterial count was lower in the absent end diastolic flow (AED) group (Table 11)

Summary

Introduction

Intrauterine growth restriction (IUGR) with impeded flow in the umbilical arteries is one of the major clinical problems in pregnancy (Kingdom, Rodeck and Kaufmann, 1997). Its pathogenetic mechanisms are still poorly understood. The prevailing views are based on the data by Trudinger et al (1985) and Giles et a1 (1985). Indicating a reduction in the density of small fetoplacental stem arterioles. Embolization studies conducted in sheep (Trudinger et al, 1987) supported the 'obliteration theory'. Detailed analysis of stem villi in IUGR with absent end diastolic flow (AED) in the umbilical arteries failed to indicate any selective loss of stem vessels (Jackson et ul, 1995; Macara et al, 1995).

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Conclusion