Influence of Swaddling Experience on Spontaneous Arousal Patterns and Autonomic Control in Sleeping Infants

ObjectiveTo investigate the effects of swaddling experience on infant sleep, spontaneous arousal patterns and autonomic control.Study designTwenty-seven healthy term infants, who were routinely swaddled at home (n = 15) or “naïve” to swaddling (n = 12), were monitored with daytime polysomnography in swaddled and unswaddled conditions at 3 to 4 weeks and at 3 months after birth.ResultsSwaddling did not alter sleep time, spontaneous arousability, or heart rate variability in routinely swaddled infants at either age. During active sleep at 3 months, cortical arousal frequency was decreased, and total sleep time was increased by swaddling in infants who were naïve to swaddling. Heart rate variability when swaddled was also highest in the naïve group.ConclusionsThe effects of infant swaddling on sleep time, arousability, and autonomic control are influenced by previous swaddling experience. Infants in the naïve to swaddling group exhibited decreased spontaneous cortical arousal, similar to responses observed in future victims of sudden infant death syndrome. Infants in unfamiliar sleeping conditions may therefore be more susceptible to cardiorespiratory challenges that fail to stimulate arousal and may lead to sudden infant death syndrome.