The brains of 1000 consecutive, clinically normal, full-term neonate without signs of perinatal distress were examined by ultrasound 3 days postpartum. We found 35 cases of intracranial haemorrhage (periventricular, choroid plexus and intraventricular); 34 possible sequelae of bleeding (subependymal and choroid plexus pseudocysts; local dilatation of the lateral ventricles) and 21 morphological aberrations. Most of these 90 abnormalities were checked several times. Four children with intracranial haemorrhage developed symptoms (3 hemipareses, 1 infantile spasm) within a year of birth. No child without sonographic abnormalities has so far been recognized as developing a clinical deficit.