Abstract Introduction Family-to-work conflict research has largely emphasized waking caregiving demands, overlooking how overnight disruptions—particularly infant sleep—shape parents’ functioning at work. Drawing from family-to-work conflict theory and organizational sleep research, we theorized that infant sleep represents a consequential overnight parental demand that influences parents’ sleep and subsequent work engagement and task performance. We further proposed that parental cognitions—specifically, beliefs about responding to infant night wakings—serve as a boundary condition that shapes these effects. Methods We conducted a preregistered, five-week within-person field study of 125 full-time working parents of infants. Infant sleep duration and quality were objectively assessed using auto-videosomnography, and parents completed twice-weekly morning and evening surveys measuring their sleep duration and quality, work engagement, and task performance. Beliefs about responding to infant night wakings were measured at baseline. Multilevel models tested direct, indirect, and moderated mediation effects. Results Infant sleep duration significantly predicted parent sleep duration (γ=.28, p.01) and sleep quality (γ=.18, p.01). Infant sleep quality predicted parent sleep quality (γ=–.029, p=.028) but not parent sleep duration (γ=.015, p=.264). Parent sleep duration mediated the effects of infant sleep duration on work engagement (indirect effect=.11, 95% CI .053, .165) and task performance (indirect effect=.11, 95% CI .061, .170). Indirect effects via parent sleep quality were nonsignificant. Parental response beliefs moderated these pathways: the indirect effects of infant sleep duration through parent sleep duration were stronger for parents higher (work engagement: .165, 95% CI .082, .243; task performance: .161, 95% CI .083, .243) versus lower in these beliefs (work engagement: .080, 95% CI .030, .129; task performance: .079, 95% CI .025, .131), with significant differences (Δ=.084 and .083, respectively). Conclusion Infant sleep is a significant and overlooked source of family-to-work conflict. Daily fluctuations in infant sleep duration undermine parent sleep—and subsequently work engagement and task performance—especially for parents who strongly believe they must respond to night wakings. These findings broaden theoretical understandings of parental demands and identify opportunities for organizations to support employees navigating infant sleep challenges. Support (if any)
Guarana et al. (Fri,) studied this question.