Diagnosis of periventricular-intraventricular hemorrhage (IVH) and its neuropathological consequences and accompaniments in the living infant has been facilitated greatly by the introduction of real-time cranial ultrasonography. The major advantages of the technique include high-resolution capability, portable instrumentation, lack of ionizing radiation, and relative affordability. Prognosis in infants with IVH relates to the mechanisms of brain injury, the most important of which are prior hypoxic-ischemic insults, posthemorrhagic hydrocephalus, and periventricular hemorrhagic infarction. The last of these is most critical and it is now clear that careful quantitative assessment of the ultrasonographic appearance of the periventricular parenchyma in the infant with IVH during the acute period of illness is of major value in estimating outcome. Prevention of IVH remains the most important goal. Prenatal interventions include prevention of premature birth (currently a very elusive goal in the United States), transportation of the premature infant to a tertiary facility in utero rather than after birth (an approach of proven value), prenatal administration of phenobarbital or vitamin K (initially promising data that require confirmation and amplification), and optimal management of labor and delivery. Postnatal interventions include careful resuscitation of newborns, correction of fluctuating cerebral blood flow velocity, correction or prevention of other major hemodynamic disturbances, and correction of abnormalities of coagulation. Of these interventions the use of muscle paralysis to correct fluctuating cerebral blood flow velocity has shown the most striking benefit vis-à-vis prevention of IVH. Postnatal pharmacological interventions that have been studied in detail include the use of phenobarbital, indomethacin, ethamsylate, and vitamin E. No single agent among this group has been shown consistently to lead to a decrease in incidence and severity of IVH.(ABSTRACT TRUNCATED AT 250 WORDS)