Scanning and transmission electron microscope study of the amniotic epithelium in the rat at the end of gestation

The pattern of the amniotic epithelium during the eight last days of pregnancy is described with the aid of scanning and transmission microscopy. A flattening of the cells appears near the term. Their area becomes progressively greater increasing their contact surface with the amniotic fluid. Simultaneaously, their microvilli become more numerous. During the 20th, the 21st and the 22nd days of pregnancy, we observed cytoplasmic processes emanating from the base of the cell interrupting the basal membrane and entering the underlying connective substance. No evidence of cell degeneration was seen