Behavior, pain perception, and the extremely low-birth weight survivor

Recognition of pain in newborns, particularly prematures undergoing intensive care, is difficult both in a clinical and a research setting. There is ample evidence that newborns, even very immature newborns, mount a hormonal, behavioral, and neural response to pain, and that pain has adverse effects on outcome. Repeated exposure to noxious stimuli and maturation of the infant change the characteristics of the responses. There is a gathering body of animal and human evidence that suggests that early pain has long-term consequences on the developing individual and prior pain experience may explain some of the behavioral characteristics described in prematures at school age in neonatal follow-up studies.