Regional variation of the vasculo-syncytial membranes in the human full-term placenta

The authors determined the frequency of vasculo-syncytial membranes in different cotyledonary regions of the full-term placenta. There were significant differences according to the site from which the sample was obtained. The highest frequency (164,3%) corresponds to the central-parabasal region of the cotyledon, close to the point of entry of the maternal blood into the intervillous space, whereas the lowest value (104,5%) corresponds to the lateral-subchorial region. The results of the present study as well as those reported by others suggest that the villi from the central-parabasal region are the best adapted ones for gas transfer between maternal and fetal blood.