Three-dimensional assessment of the morphology of the umbilical artery in normal and pre-eclamptic placentas

Abstract

Aim: Pre-eclampsia is one of the main causes of intrauterine growth retardation. Although there are many studies performed in this setting showing the course of the umbilical vessels within the umbilical cord along with its structural changes, studies are lacking with regard to intraplacental vasculature and its structural changes.

Methods: We investigated whether the vascular pattern differed in preeclamptic placentas in terms of intraplacental course and morphometry of the umbilical artery by using vascular corrosion cast technique. Furthermore, cross-sections taken from umbilical artery branches at different levels within the placenta, were examined with both light and scanning electron microscopy (SEM).

Results: Vascular corrosion casts generated in both pregnancy groups should be defined with the main umbilical artery divided into 2-4 primary branches. No significant difference was seen between normal and pre-eclamptic groups regarding the diameters of primary and secondary branches and the number of cotyledons contained (P > 0.05). However, microscopic studies demonstrated expanded intervillous spaces in the placentas of pre-eclamptic pregnancies. Under SEM, distortion on the endothelial surface of the umbilical artery and an increase in vessel diameter and wall thickness have been determined in pre-eclamptic placentas. Furthermore, the branching pattern and changes affecting the endothelial surface of the umbilical artery have been shown three-dimensionally in pre-eclamptic placentas, using corrosion cast technique and SEM, respectively.

Conclusion: While microscopic findings were consistent with the Doppler ultrasonography findings, namely higher systole/diastole ratio and increased resistance (RI) and pulsatile (PI) index in the umbilical artery, no clear morphometric change has been observed.