Association between mealtime regularity and postpartum depression in first-time Japanese mothers: a cross- sectional study

Purpose Postpartum depression (PPD) is a common mental health condition that negatively affects maternal wellbeing and child development. Although daily lifestyle behaviors have been implicated in PPD, the roles of breakfast skipping and mealtime regularity, which are key components of chrononutrition, remain insufficiently understood. This study examined the associations between mealtime regularity and postpartum depressive symptoms in first-time Japanese mothers. Methods This cross-sectional study included 841first-time Japanese mothers with a child aged 0–12 months (UMIN000051573; approved on July 10, 2023). Depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS). Mealtime regularity and breakfast frequency were evaluated using self-administered questionnaires. Furthermore, associations between EPDS scores and eating-related behaviors were examined using generalized estimating equations, after adjusting for sociodemographic factors, health-related behaviors, mothers’ and infants’ sleep characteristics, and partners’ working days. Results Mothers with regular mealtime had significantly lower EPDS scores than those with irregular mealtime. After full adjustment for potential confounders, regular mealtime remained independently associated with lower EPDS scores, whereas breakfast skipping was not. Conclusion Regular mealtime, rather than breakfast consumption, was independently associated with fewer postpartum depressive symptoms. These findings suggest that the temporal organization of eating behaviors may represent a novel and modifiable lifestyle factor relevant to postpartum mental health. Further longitudinal and interventional studies are warranted to clarify causality and evaluate mealtime regularity as a potential target for PPD prevention.