Temperament and increased weight gain in infants.

The role of temperamental characteristics in accelerated and decelerated weight gain in normal infants has not been investigated previously except for differences in activity. The present study drew a random sample of 200 normal infants from a largely middle-class private practice. It found 24 infants who gained 30 or more percentile points in weight for length determinations between 6 and 12 months of age and 25 who lost 20 percentile points or more. These growth data were compared with contemporaneous findings on the Infant Temperament Questionnaire. Those gaining the most had significantly more difficult temperament ratings (p less than 0.05) and were perceived by their mothers as "more difficult than average" (p less than 0.001). Infants with the most decelerated growth were not temperamentally different from the general sample. Negative mood rather than low activity was the specific characteristic distinguishing the infants gaining the most (p = 0.006). Clinical experience would suggest that fussy infants are fed more to quiet them.