Placental morphology in spontaneous human abortuses with normal and abnormal karyotypes.

A systematic gross and microscopic study of the placenta was done on human spontaneous abortions, correlating placental morphology and karyotype of the conceptus. Consistent abnormalities were seen in the four major forms of human heteroploidy, so that a fairly accurate ""karyotypic diagnosis'' could be made from careful gross and microscopic examination of the aborted material. Depressed growth activity and dysmorphogenesis characterized these placentas, reflecting placental participation in the disturbed phenotypic expression of heteroploidy.