Low intelligence. Its relation to length of gestation and rate of foetal growth.

More information is required about three aspects of the relation of low intelligence to birthweight and length of gestation: (I) Low birthweight is known to be associated with mental subnormality, but the significance of this remains unknown. (2) High birthweight has been reported to occur more frequently in association with subnormality, but the evidence is inconclusive. (3) Prolonged gestation has been suggested as a cause of cerebral damage and consequent intellectual impairment, but no data bearing on this issue appear to have been published. In this paper some observations which are relevant to these problems will be described.