Retardation of neuronal maturation in premature infants compared with term infants of the same postconceptional age.

Neuronal morphologic development and the number of soma and spines in the visual cortex were investigated. Ten premature infants surviving at least three weeks were compared with control infants who had been born at term gestation and had the same postconceptional age. In six cases of sudden infant death syndrome, bronchopulmonary dysplasia, or patent ductus arteriosus, neuronal development was similar to that in the control cases. The persistence of immature neurons in two of the remaining four cases suggested a developmental neuronal delay or arrest.