A longitudinal study of the links between maternal and infant nocturnal wakefulness.

STUDY OBJECTIVES: To examine the longitudinal links between maternal and infant nocturnal wakefulness by employing a trajectory-based approach, and to assess whether the strength of these links differs as a function of sleep assessment method (actigraphy vs. self-report) and sleeping arrangements. METHODS: Maternal and infant nocturnal wakefulness were assessed with actigraphy and sleep diaries at home for 5 nights, at 3 (N = 191), 6 (N = 178), 12 (N = 155), and 18 (N = 135) months postpartum. Outcome measures included the number of night-wakings (NW) and the length of nocturnal wakefulness (WASO). RESULTS: Strong associations between maternal and infant nocturnal wakefulness (controlling for nighttime breastfeeding) were found for NW and WASO. Trajectory analyses demonstrated that the strength of these relations decreased linearly from 3 to 18 months. Furthermore, the findings showed that the links between maternal and infant NW and WASO were stronger for maternal reports than for actigraphy. No consistent differences were found in the strength of the relations between maternal and infant NW and WASO as a function of sleeping arrangements (ie, room-sharing vs. solitary-sleeping families). CONCLUSIONS: The results suggest that infant and maternal sleep are strongly intertwined, especially during the first 6 months. The decline in the synchronization between maternal and infant nocturnal wakefulness through infant development may be attributed to the growing ability of infants to self-soothe during the night. The findings emphasize the need to study sleep within a family context.