Developmental outcome in very low birth weight infants 6 to 36 months old.

A cohort of 78 infants weighing less than 1500 g at birth was followed prospectively to determine the impact of birth weight, age of assessment, and skill area on their developmental performance. Five skill areas were tested using the Griffiths Mental Scales of Development at 6, 12, 24, and 36 months of age. Infants were divided into three birth weight groups: less than 750 g, 750-1000 g, and 1001-1500 g. A significant age and skill interaction was found, with the locomotor and eye-hand skills decreasing consistently over time, and the personal-social and hearing and speech skills initially decreasing and then rising from 12 to 36 months. Infants born at less than 1000 g consistently performed more poorly than those born at 1001-1500 g. Explanations for the variation in scores and the implications of these findings to the evaluation of low birth weight infants are discussed.