Sleep fragmentation and evidence for sleep debt in alcohol-exposed infants

Background: Infants exposed prenatally to alcohol are at increased risk for poor neurodevelopmental outcome including Sudden Infant Death Syndrome. Aim: To examine the relationship between prenatal alcohol exposure, sleep, arousal and sleep-related spontaneous motor movements in early infancy. Study design: Low-income women ( N =13) were interviewed regarding pre- and pregnancy rates of alcohol, cigarette smoking and other substance use in the perinatal period. Infants were examined in a laboratory nap study using EEG, videography and actigraphy at 6–8 weeks of age. Estimates of maternal pre- and pregnancy alcohol use were used to divide infants into high vs. low maternal alcohol use groups. Subjects: Mother–infant dyads recruited from a family practice clinic. Outcome measures: Sleep-related spontaneous movements, behavioral state, and maternal assessments of infant alertness and irritability. Results: Pre-pregnancy rates of alcohol consumption including binge drinking correlated with maternal report of poor infant alertness, and increased irritability. High maternal exposure groups showed increased sleep fragmentation, e.g. frequency and duration of wakefulness following sleep onset and decreased active sleep. Bout analysis of the temporal structure of sleep-related spontaneous movements showed significantly reduced bout duration associated with high maternal alcohol use. Conclusion: These results present evidence that prenatal alcohol exposure disrupts postnatal sleep organization and suppresses spontaneous movements during sleep, and increased sleep fragmentation promotes sleep deprivation. Results are consistent with the SIDS model of chronic sleep debt and suggest that attenuated sleep-related movements should be examined as an important modulator of cardiorespiratory functions during sleep in high-risk groups.