Abstract
The human placental villi in the first, second and third trimester of normal pregnacy, in the cases of toxemia of the late pregnancy and of small for date and large for date of pregnancy, were studied by scanning and transmission electrcn microscope.
1. Scanning electron microscope During the first trimester of pregnancy, the placental villi had thick stems with a small number of branches and many sprouts. In the second trimester, the sprouts grew spreading many branches and became showing a treelike as a whole at the terminal stage of pregnancy.
2. Transmission electron microscope
Throughout the course of pregnancy, the merging of syncytial cells was noted, the number of the Langhans cells decrased and the stromal capillary vessels and intervillous spaces were closer to each other, while any change of basement membrane was not evident. 3. Abnormal changes in the villi of the term placenta of the toxemia, SFD and LFD.
a. The irregular branches, the coarse stumpy appearance of the microvilli and the marked change of syncytial nuclei were observed in the placental villi of toxemia as compare to those in normal pregnancy.
b. In the cases of SFD, decrease in number of the branches of the villi, defect of microvilli and many myeline structures were observed in syncytial cells.
c. In the placental villi of LFD, many complicating branches of the villi, clump of microvilli, and increase in numbers of the mitochondria, Golgi apparatus endoplasmic reticulum were observed.
