Biobehavioral characteristics of infants with failure to thrive.

Failure to thrive (FTT) is a syndrome of growth failure that results in an infant who is behaviorally difficult. The current thinking is that FTT results from a problematic infant-mother interaction, with the infant making a significant contribution to the interactional process. It is possible that the behavioral characteristics of the infant with FTT may be related to underlying physiologic response patterns, specifically, activity of the autonomic nervous system. The purpose of this study is to examine the relationships among behavioral responsiveness, heart rate variability as a marker of autonomic nervous system activity, and nutritional status in infants with FTT. Infants with FTT were matched with healthy growing infants (n = 14 pairs). Results from the study indicated that infants with FTT exhibited considerably more negative behaviors and exhibited low heart rate variability. It appears that there may be a physiologic basis to the behaviors that are exhibited by infants with FTT. Prospective research is needed to further clarify this relationship.