Normative early head growth in very-low-birth-weight infants.

Normative head growth curves were developed from serial weekly measurements of head circumference in 50 infants with birth weights less than 1500 gm who had good neurodevelopmental outcome at 2 years of age (assessed by neurologic examination and by the Bayley Mental Developmental Scale). Forty-one of the infants with good outcome were normocephalic at birth; after head shrinkage during the first week of life, increments in head circumference averaged 0.49 cm during the second week, 0.79 cm during the third week, and 0.95 cm per week thereafter. Nine infants with good outcome were microcephalic at birth; these infants had no head shrinkage during the first week of life and had a significantly greater mean weekly increment in head circumference of 0.98 cm (P less than 0.008). In contrast, 10 normocephalic and seven microcephalic infants with poor outcome had significantly less postnatal head growth (P less than 0.02 and p less than 0.001, respectively). Head growth curves developed from measurements in infants with documented good short-term developmental outcome are the most appropriate standards for head growth for very-low-birth-weight infants.