Maternal Adverse Childhood Experiences and Delayed Initiation of Complementary Foods: A Nationwide Online Cohort Study

<b>Background/Objectives:</b> Infant feeding is critical for health and development, yet the influence of maternal psychosocial factors on its timing is not fully understood. While maternal adverse childhood experiences (ACEs) are known to affect perinatal outcomes, their impact on the specific timing of initiating formula and complementary foods remains under-investigated. We hypothesized that maternal ACEs are associated with delayed initiation of infant formula and complementary foods and that this association is mediated by postpartum depression (PPD). This study aimed to examine the link between maternal ACEs and delayed infant feeding, and to assess the mediating role of PPD using data from a large nationwide Japanese database. <b>Methods:</b> This cross-sectional study utilized data from the Japan COVID-19 and Society Internet Survey (JACSIS), conducted between July and August 2021. The analysis included 3446 postpartum mothers. Maternal ACEs were assessed using a 9-item questionnaire, and a cumulative score was categorized as high (≥4 ACEs) versus low (0-3 ACEs). The primary outcomes were infant feeding behavior including breastfeeding, formula feeding and complementary foods. We used logistic regression analysis with inverse probability of treatment weighting (IPTW) to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). A mediation analysis was conducted to evaluate the role of smoking, alcohol and PPD. <b>Results:</b> High ACE exposure (≥4) was present in 221 mothers (6.4%). A high maternal ACE score was significantly associated with delayed initiation of formula feeding (≥7 days) (Adjusted OR: 2.12, 95% CI: 1.12-4.01, <i>p</i> = 0.02) and late initiation of complementary foods (≥7 months) (Adjusted OR: 2.27, 95% CI: 1.38-5.01, <i>p</i> = 0.03); no significant associations were observed for ever/late/continued breastfeeding or ever/continued formula feeding. These associations attenuated to non-significance after adjusting for PPD. <b>Conclusions:</b> Maternal ACEs are associated with delayed initiation of complementary foods and formula, largely through PPD. Perinatal services should combine ACE/PPD screening with trauma-informed mental health and nutrition support to promote timely infant feeding.