Intergenerational support, conflict, and postpartum depression trajectories among Chinese mothers: Family-based care and multilevel predictors

Background Postpartum depression (PPD) remains a major public health concern. In China, the postpartum period is embedded within a family-based caregiving system characterized by intensive intergenerational involvement. Within this context, intergenerational support (IS) and intergenerational conflict (IC) often coexist, forming a distinct stress-regulation environment. Guided by the stress-buffering model of social support, this study conceptualizes the Chinese postpartum family as a dynamic system in which IS and IC jointly shape maternal mental health over time. Methods A four-wave longitudinal design was employed. Parallel Process Latent Growth Curve Modeling (PP-LGCM) was used to examine the co-developmental trajectories of IS, IC, and PPD symptoms. Logistic regression analyses were conducted to identify multilevel predictors of trajectory subgroups. Results The prevalence of elevated depressive symptoms (EPDS ≥ 9) ranged from 23.1% to 24.2% across assessments, while probable PPD (EPDS ≥ 13) ranged from 4.6% to 7.2%. PP-LGCM identified five distinct joint trajectory classes: Moderate-risk group ( n = 30; 8.6%), Mild-risk group ( n = 103; 29.7%), Improving group ( n = 45; 13.0%), Resistant group ( n = 139; 40.1%), and High-risk group (n = 30; 8.6%). Trajectory membership was significantly associated with living arrangement, sleep quality, psychological flexibility, and partner relationship. Conclusions In the urban Chinese postpartum context, PPD symptom trajectories are closely linked to intergenerational family dynamics. These findings underscore the need for family-based prevention and treatment that, when feasible, engages parents/parents-in-law (and partners) to align caregiving expectations and roles, particularly for women in high-risk or worsening trajectory subgroups.