[Pathology of placenta from small for gestational age infants]

Pathologic study was carried out in 125 placentas, of which 25 were from cases of small for gestational age infants (SGA) and 100 from normal pregnancies. Ultrastructural study was done in 5 cases of each group. In the SGA group placenta circumvallata and velamentous insertion of cord were more frequently seen and the percentages of syncytial knots, cytotrophoblastic cells, and fibrinoid necrosis, stromal fibrosis and obliterative endarteritis of chorionic villi were also higher. Deficiency of vasculo-syncytial membranes and unduly thick trophoblastic basement membranes were common features of the SGA placentas. The most significant ultrastructural finding was the spasticity of capillaries of the villous stroma. It is believed that insufficient utero-placental blood flow may lead to the occurrence of SGA infants.