[Scanning electron microscopy observations on the vascular casts of the placental chorion in normal pregnancy and pregnancy-induced hypertension].

The method of vascular casting in human placental chorion for scanning electron microscopy (SEM) was described. Through SEM of the placental chorion in five normal pregnant cases and twenty-two pregnancy induce hypertension (PIH), the three-dimensional angioarchitecture of the placental chorion in normal pregnancy and PIH of different clinical classes were clarified. Increasing with the severity of PIH, the capillaries in the placental chorion became more and more attenuated and irregular in diameter, with their branches decreasing in number and the inner wall roughened. These capillary changes were found even in mild PIH. However, the pathological changes in the chorionic capillaries in moderate and severe cases treated beforehand with magnesium sulfate were much less than those in untreated cases.