Intraventricular hemorrhage (IVH)
IVH describes bleeding from the subependymal matrix (the origin of fetal brain cells) into the ventricles of the brain. The blood vessels around the ventricles develop late in the third trimester, thus preterm infants have underdeveloped periventricular blood vessels, predisposing them to increased risk of IVH. The risk of CP increases with the severity of IVH.
Periventricular leukomalacia (PVL)
IVH is a risk factor for PVL, but PVL is a separate pathological process. The pathogenesis of PVL arises from two important factors: (1) ischemia/hypoxia and (2) infection/inflammation.