Nighttime sleep duration declines after the transition to grandparenthood, with more sustained reductions among men than women, concentrated in the maternal lineage and among non-employed maternal grandmothers and non-coresiding maternal grandfathers.
Key Findings
Results
Nighttime sleep duration declines after the transition to grandparenthood, with the reductions being more sustained among men than women.
Among men, sleep duration decreases from birth of the grandchild and remains lower for up to nine years post-transition.
Among women, declines are smaller and limited to specific post-transition years rather than sustained across the full follow-up period.
Little evidence of changes in sleep duration was found before the transition, suggesting the effect is specific to the post-transition period.
The study used fixed-effects models with event-time indicators to trace sleep trajectories before and after the transition.
Results
Sleep onset timing and nap duration remain stable across the transition to grandparenthood.
No significant changes in sleep onset timing were detected before or after the transition to grandparenthood.
Nap duration also showed no meaningful changes associated with the grandparenthood transition.
This contrasts with nighttime sleep duration, which did show post-transition declines.
Results
Reductions in sleep duration are concentrated in the maternal lineage rather than being uniformly distributed across grandparental roles.
Stratified analyses revealed differences by both grandparental sex and parental lineage (maternal vs. paternal).
Non-employed maternal grandmothers showed concentrated sleep duration reductions after the transition.
Non-coresiding maternal grandfathers showed declines in sleep duration after the transition.
Maternal grandfathers showed declines shortly after the transition regardless of their employment status.
Results
Employment status and living arrangement showed limited moderating effects on sleep duration changes across the grandparenthood transition.
Notable exceptions include non-employed maternal grandmothers and non-coresiding maternal grandfathers, who showed concentrated sleep reductions.
Otherwise, employment status and coresidence did not substantially moderate the association between grandparenthood transition and sleep duration changes.
This suggests the effects are not uniformly explained by increased caregiving opportunity or access.
Methods
The study used six waves of longitudinal data from the China Family Panel Studies (CFPS, 2010–2022) to examine within-individual sleep changes around grandparenthood.
Data spanned six waves from 2010 to 2022, enabling examination of trajectories up to nine years post-transition.
Fixed-effects models were used to control for time-invariant individual characteristics, allowing within-individual comparisons.
Event-time indicators were employed to trace sleep trajectories both before and after the transition to grandparenthood.
The study examined sleep duration, sleep onset timing, and nap duration as separate outcomes.
Results
The study found little evidence of anticipatory changes in sleep duration before the transition to grandparenthood.
Pre-transition event-time indicators showed little evidence of sleep changes leading up to the birth of a grandchild.
This pattern supports interpreting post-transition changes as responses to the transition rather than pre-existing trends.
The absence of pre-transition changes helps rule out selection effects in the fixed-effects framework.
What This Means
This research suggests that becoming a grandparent for the first time is associated with sleeping less at night, but the effect differs considerably depending on whether the grandparent is a man or a woman, and whether their grandchild is on their son's or daughter's side of the family. Men experienced more lasting reductions in nighttime sleep — lasting up to nine years — while women's sleep reductions were smaller and occurred only in certain years after the transition. Importantly, the timing of when people fall asleep and how long they nap during the day did not appear to change meaningfully around this life event.
The research also found that the sleep reductions were not spread equally across all types of grandparents. They were most concentrated among maternal grandparents — meaning grandmothers and grandfathers on the mother's side of the grandchild. Specifically, maternal grandmothers who were not employed and maternal grandfathers who did not live with the grandchild showed the clearest sleep reductions. This pattern points to the likely role of childcare demands, as maternal grandparents are typically more involved in hands-on caregiving in Chinese families.
This research matters because it highlights that a major life transition in middle and later adulthood — becoming a grandparent — can have measurable consequences for sleep health, which is closely tied to overall physical and cognitive well-being. The findings suggest that the experience of grandparenthood is far from uniform: a person's sex, their family role (maternal vs. paternal side), employment, and living situation all shape how this transition affects their sleep. Understanding these differences could help identify which grandparents may be at greater risk for sleep disruption as they take on new caregiving responsibilities.
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Chen J. (2026). Bittersweet transition: sex- and lineage-specific changes in sleep duration and timing across first-time grandparenthood.. The journals of gerontology. Series B, Psychological sciences and social sciences. https://doi.org/10.1093/geronb/gbag077