A longitudinal study of the bi-directional relations between parental bedtime and nighttime involvement and infant sleep

Objective: This longitudinal study assessed the prospective bidirectional links between parental involvement during bedtime and nighttime and infants' sleep during the first year of life. Methods: The sample included 207 families at 4 months, 177 at 8 months, and 154 at 12 months. Infant sleep was assessed at home for seven nights using actigraphy, sleep diaries, and the Brief Infant Sleep Questionnaire (BISQ). Parental bedtime and nighttime involvement were reported daily by parents through sleep diaries at all time points. Results: Concomitant associations (controlling for sleeping arrangements) were found between parental bedtime and nighttime involvement and between infant objective and reported sleep quality measures (i.e., number of night-wakings, wake after sleep onset [WASO], and subjective infant sleep problems). Structural Equation Modeling analyses demonstrated significant prospective associations: Higher parental bedtime involvement at 4 months predicted an increase in infant number of night-wakings from 4 to 8 months. Moreover, higher levels of parental bedtime and nighttime involvement at 8 months predicted an increase in infant WASO from 8 to 12 months. Only one SEM model demonstrated a significant cross-lagged link from infant sleep quality to parental involvement: More perceived infant sleep problems at 4 months predicted a decrease in parental bedtime involvement from 4 to 8 months. Conclusions: The findings suggest that higher levels of parental involvement in soothing the infant to sleep at bedtime and nighttime predict poorer infant sleep quality. Only limited evidence was found for infant-driven links.