The Pathogenesis of Preterm Brain Injury

Premature birth remains a major cause of morbidity and mortality. Although there have been marked improvements in the survival of preterm infants, this has not been matched by a corresponding improvement in morbidity. Although there is some evidence for modest improvements in survival without disability in modern cohorts, others report no apparent improvement and even increases in disability after extremely preterm (<25 weeks’ gestation) birth. Traditionally, brain injury in preterm infants was thought to reflect a fundamental vulnerability of the developing periventricular white matter to damage. However, recent evidence suggests a much more complex picture. In the present chapter, we will critically dissect the neuropathology of preterm brain injury, including the timing of injury, the association of hypoxia–ischemia and infection/inflammation with adverse outcomes, and the importance of impaired maturation and late evolving injury of both white and gray matter regions, and highlight key unresolved issues.