To assess how well early ultrasound lesions in preterm newborns predict reduced head circumference at 2 years, the investigators followed 923 children born before the 28th week of gestation who were not microcephalic at birth. Six percent of children who had a normal ultrasound scan were microcephalic compared with 15% to 20% who had intraventricular hemorrhage, an echolucent lesion, or ventriculomegaly. The odds ratios (95% confidence intervals) for microcephaly associated with different ultrasound images were intraventricular hemorrhage, 1.5 (0.8-3.0); ventriculomegaly, 3.3 (1.8-6.0); an echodense lesion, 1.6 (0.7-3.5); and an echolucent lesion, 3.1 (1.5-6.2). Ventriculomegaly and an echolucent lesion had very similar low positive predictive values (24% and 27%, respectively) and high negative predictive values (91% and 90%, respectively) for microcephaly. Ventriculomegaly had a higher sensitivity for microcephaly than did an echolucent lesion (24% vs 16%, respectively). Focal white-matter lesion (echolucent lesion) and diffuse white-matter damage (ventriculomegaly) predict an increased risk of microcephaly.