To evaluate the developmental correlates of microcephaly evident at birth and at 2 years in a cohort born at extremely low gestational age.
We assessed development and motor function at 2 years of 958 children born before the 28th week of gestation, comparing those who had microcephaly at birth or 2 years with children with normal head circumference while considering the contribution of neonatal cranial ultrasound lesions.
A total of 11% of infants in our sample had microcephaly at 2 years. Microcephaly at 2 years, but not at birth, predicts severe motor and cognitive impairments at 2 years. A total of 71% of children with congenital microcephaly had a normal head circumference at 2 years and had neurodevelopmental outcomes comparable with those with normal head circumference at birth and 2 years. Among children with microcephaly at 2 years, more than half had a Mental Developmental Index <70, and nearly a third had cerebral palsy. The risks were increased if the child also had cerebral white matter damage on a cranial ultrasound scan obtained 2 years previously.
Among extremely low gestational age newborns, microcephaly at 2 years, but not at birth, is associated with motor and cognitive impairment at age 2.