[Placental morphometry in diastolic zero and negative flow of the umbilical arteries]

Macromorphometric and histometric placental data, in cases with enddiastolic zero flow or reverse flow (dZRF), reveal a lower placental weight and smaller attachment area as well as bigger terminal villi with a reduced amount of epithelial plates with comparable vascularisation. In cases with reverse flow, all parameters were worse, either compared to the controls or to the zero flow cases. With advancing duration of clinical observation, we find a maturation of the terminal villi, with the cross-sectional areas getting smaller, diffusion distances becoming shorter and vessels bigger. This proves the dependence of foetal outcome by dZRF on the compensatory capacity of the terminal villi. The planimetric area in the forward flow channel depends on the foetal intravillous blood volume.