The very preterm infant is uniquely vulnerable to bleeding into the cerebral ventricles because of the numerous but unsupported blood vessels in the subependymal germinal matrix and unstable blood pressure and flow resulting from preterm delivery and respiratory distress. Approximately 25% of infants whose birthweights are 500 to 1,500 g have some intraventricular hemorrhage (IVH). Even a small IVH is associated with an increased risk of disability. A large IVH is sometimes complicated by hemorrhagic parenchymal infarction (also known as grade 4 IVH), which is believed to arise when venous occlusion from hematoma impairs perfusion in periventricular white matter. Large unilateral infarctions are usually associated with contralateral hemiparesis, but cognitive function may be less impaired. Prenatal glucocorticoid therapy reduces IVH by nearly 50% in randomized trials. Postnatal indomethacin reduces IVH, but reduced disability has not been consistently documented.