Anthropometry of fetal vasculature in the chorionic plate

Abstract

Normal fetal development is dependent on adequate placental blood perfusion. The functional role of the placenta takes place mainly in the capillary system; however, ultrasound imaging of fetal blood flow is commonly performed on the umbilical artery, or on its first branches over the chorionic plate. The objective of this study was to evaluate the structural organization of the feto-placental vasculature of the chorionic plate. Casting of the placental vasculature was performed on 15 full-term placentas using a dental polymer mixed with colored ink. Observations of the cast models revealed that the branching architecture of the chorionic vessel is a combination of dichotomous and monopodial patterns, where the first two to three generations are always of a dichotomous nature. Analysis of the daughter-to-mother diameter ratios in the chorionic vessels provided a maximum in the range of 0.6-0.8 for the dichotomous branches, whereas in monopodial branches it was in the range of 0.1-0.3. Similar to previous studies, this study reveals that the vasculature architecture is mostly monopodial for the marginal cord insertion and mostly dichotomous for the central insertion. The more marginal the umbilical cord insertion is on the chorionic plate, the more monopodial branching patterns are created to compensate the dichotomous pattern deficiency to perfuse peripheral placental territories.

Fig. 1

Mapping the branching network of the chorionic vasculature. (a) Identification of generation numbers and labels of branching vessels on a placental cast. The branching network is of one umbilical artery. The second artery had a much smaller network and is only partially visible in this figure. (b) Drawing of the arterial vasculature of the cast shown in (a) with vessel labels.

Fig. 2

Placental casts. (a) Central cord insertion; both umbilical arteries were injected with red ink. (b) Marginal cord insertion; one artery was injected with white and the other with red ink.

Fig. 3

Histograms of daughter-to-mother diameter ratios (D_d/D_m for given ranges) for each generation of the chorionic arteries: (a) dichotomous branching pattern; (b) monopodial branching pattern.

Fig. 4

Schematic description of a typical geometry for a network branching off an umbilical artery. The red points denote the generation number and the vessels are labeled.

Fig. 5

Schematic description of hypothetic organizations for the chorionic plate vessels. (a) Pure dichotomous branching pattern for a central insertion. (b) Pure dichotomous branching pattern for a marginal insertion. (c) Pure monopodial branching pattern for a marginal insertion.