Chronodisruption during Pregnancy Mediates the Relationship between Social Disadvantage and Reduced Brain Maturation in Neonates

Prenatal exposure to adversity profoundly impacts offspring development. Well-documented disparities in sleep and circadian health are known to be related, and exposure to disrupted maternal sleep and circadian rhythms during pregnancy may have an effect on offspring neurodevelopment. The current study explored the association between maternal sleep and circadian rhythm disruption during pregnancy and infant brain outcomes at birth, examining sleep and circadian rhythm disruptions as a possible mediator of the effect of adversity during pregnancy on infant structural brain outcomes in 148 mother-child dyads. Maternal sleep was quantified using actigraphy data collected during each trimester of pregnancy and quantified using a measure of chronodisruption (irregularity in the sleep schedule) and a measure of chronotype (sleep timing). Adversity was quantified using a latent factor of several metrics of social disadvantage (e.g., income-to-needs ratio). Infant structural brain outcomes at birth including cortical gray matter, subcortical gray matter, and white matter volumes along with a measure of cortical folding reflecting the total surface area of the cortex. Findings indicated that chronodisruption during pregnancy was associated with smaller infant cortical gray matter, subcortical gray matter, and white matter volumes and less cortical folding at birth, with infants of mothers with later chronotypes evidencing smaller subcortical gray matter volumes. Chronodisruption during pregnancy mediated the association between maternal social disadvantage and structural brain outcomes. Findings highlight the importance of regularity and rhythmicity in sleep schedules during pregnancy and highlight the role of chronodisruption as a mechanism of the deleterious neurodevelopmental effects of prenatal adversity. Significance Statement This study examined the effect of exposure to maternal sleep and circadian rhythm disruptions during pregnancy on neonatal brain structure. Sleep and circadian disruptions were associated with global differences in neonatal brain structure. Mothers who had more irregular sleep schedules during pregnancy had infants who had smaller total cortical gray matter, subcortical gray matter, and white matter volumes and less cortical folding at birth. Irregular maternal sleep schedules during pregnancy mediated the association between adversity and structural brain outcomes, suggesting that sleep and daily rhythm disturbances may be one pathway through which adversity shapes offspring neurodevelopment. Findings imply that modifying the work schedules of pregnant women to avoid swing or night shifts might be beneficial for enhancing child neurodevelopment.