0330 Understanding Postpartum Sleep: Mutual Associations Between Maternal and Infant Sleep

Abstract Introduction Maternal and infant sleep are closely interconnected in the early postpartum period, with infant nighttime behaviors known to disrupt maternal sleep continuity and maternal sleep patterns playing a role in caregiving responses. Although infant-to-maternal disruption is well recognized, fewer studies have examined mutual sleep associations using subjective daily measures. Understanding mother-infant sleep dynamics is important, as sleep fragmentation contributes to fatigue, mood disturbance, and caregiving strain in new mothers. Methods Participants included 16 mother–infant dyads from a longitudinal perinatal study. At 6 weeks postpartum, mothers completed the Pittsburgh Sleep Quality Index (PSQI) to assess maternal sleep and the Infant Sleep Questionnaire (ISQ) to assess infant sleep behaviors. At 16 weeks, mothers completed daily sleep diaries for themselves and their infants across four consecutive days. Infant variables included average night waking frequency and average resettling duration. Maternal variables included diary-based total sleep time, daily perceived sleep quality, and PSQI global scores. Linear regressions tested infant-to-maternal and maternal-to-infant sleep associations, adjusting for the corresponding 6-week sleep variables as baseline covariates. Results The model predicting maternal total sleep time was significant (R² = .55, F(3, 12) = 4.84, p = .019). Infant resettling duration significantly predicted shorter maternal sleep (b = 0.046, p = .012; β = .593) and poorer baseline maternal sleep quality also predicted shorter sleep (b = −0.33, p = .013; β = −.584). Infant night wakings were not significant (β = .005). A model predicting average maternal sleep quality was also significant (R² = .65, F(3, 12) = 7.34, p = .005). Baseline PSQI predicted poorer 16-week sleep quality (p = .0015; β = −.721). Infant night wakings showed a trend toward poorer sleep (p = .085; β = −.324), while resettling duration was not significant (β = .201). Maternal-to-infant sleep models were not significant (ps ≥ .38). Conclusion Findings highlight robust infant-to-maternal effects at 16 weeks postpartum. Infant nighttime regulation, particularly resettling duration, emerged as a key contributor to maternal sleep, whereas maternal sleep quality was shaped by baseline sleep patterns. Results underscore the importance of supporting infant nighttime regulation and resettling as a pathway to improving early postpartum sleep health. Support (if any)