Infarctions and intervillous thrombosis in placenta, and their association with intrauterine growth retardation.

The number of infarctions and intervillous thromboses have been determined in a randomized, optimal obstetric material, consisting of 301 placentae. All the placentae were examined without knowledge of the pregnancies, deliveries or infants. They were examined macroscopically and histologically. The total content of protein, RNA and DNA were determined in a randomized sample of the 301 placentae. Fifty-two placentae had small infarctions, and the corresponding birth weights, placental weights and placental DNA were of the same magnitude as in the remainder of the material. There was the same frequency of infarctions among the placentae with intervillous thrombosis. There were 11 with intervillous thrombosis, and they had a significant reduction in infant birth weight and in placental content of DNA. A significant part of these (6) had asphyxia at birth. In neither of the groups was there proliferation of Langhans cells as a sign of longer lasting anoxia. The extent of villous fibrosis in the groups was the same as in the remainder of the material. It is concluded, that no evidence was found to support a theory that infarctions and intervillous thromboses have the same pathogenesis.