Developmental testing of pre-term and small-for-date infants.

Twenty-five full-term, newborn infants and 22 small-for-date infants born at term had comparable nerve conduction velocities and were considered to be of equal neurological maturity. Twenty-six pre-term infants equal in weight to the small-for-date infants had significantly slower nerve conduction velocities and were considered on this basis more immature at birth than the term and small-for-date infants. All of these infants were given Gesell developmental tests at approximately 40 weeks of age by an examiner with no knowledge of their neonatal condition. The objective was to determine to what degree performance later in infancy is dependent on neurological maturity at birth. The full-term infants and the small-for-date infants performed at their age level with average developmental quotients of 99 and 96, respectively. The pre-term infants performed at less than their age from birth with an average D.Q. of 88; but, when their age was corrected for weeks of prematurity, the average D.Q. was 99. These findings substantiate the concept that performance on the Gesell schedules is dependent on time from conception rather than time from birth. Preterm infants should have their age determined from their expected date of birth for purposes of calculating a developmental quotient.