[Morphological and clinical studies on the chorionic vessels--a proposal of a vascular type]

The subchorionic artery is usually thinner than the vein (A less than V) in term placenta. However, this may not hold true in some areas (A greater than or equal to V, A much less than V). In A greater than or equal to V areas, vasculo-syncytial membrane (VSM) formation became poorer in peripheral villi, and stromal fibrosis was observed. VSM formation was also poor in the placenta with A much less than V, but stromal fibrosis was not seen. Birth weight, placental weight, urinary E3 and serum hPL levels and Apgar score became lower as the scope of distribution of A greater than or equal to V areas was increased. When subchorionic ramal arteries were markedly thinner than veins over almost all the placenta (A much less than V), birth weight and urinary E3 levels were low but placental weight, Apgar score and serum hPL levels did not decrease, and the incidence of cardiac diseases was definitely high in infants. This suggests that the observation of the placental vascular type may serve as an effective and convenient method of screening for newborn with cardiac diseases. These findings suggested that A much less than V is mainly related to the fetus, while A greater than or equal to V is mainly related to the placenta.