Mother-infant bonding can buffer long-term effects of postpartum depression on child outcomes

Postpartum maternal mental health and mother-to-infant bonding are well-established as critical factors in a child's psychosocial development. However, few studies have explored the combined impact of postpartum maternal depression and early bonding experiences on emotional and behavioral difficulties during middle childhood. A new study reveals significant associations between postpartum depression, mother-to-infant bonding, and child difficulties. Notably, secure early bonding was found to partially buffer the long-term effects of postpartum depression on child outcomes.

The development and well-being of a child are shaped by various factors, among which maternal mental health and mother-to-infant bonding play a significant role in social and emotional development. Infants of mothers with postpartum depression often exhibit erratic temperaments and delayed cognitive development. Moreover, maternal depression can hinder the bonding process, increasing the risk of insecure attachment and subsequent developmental challenges. While the short-term effects of postpartum depression on early child development and bonding are well-documented, less is known about how maternal depression and bonding difficulties jointly influence behavioral and psychosocial outcomes in middle childhood.

To address this gap, a research team led by Associate Professor Daimei Sasayama from the Department of Psychiatry in collaboration with Professor Hideo Honda from the Department of Child and Adolescent Developmental Psychiatry, Shinshu University School of Medicine, Japan, investigated the relationship between postpartum maternal depression and mother-to-infant bonding and their combined impact on children's emotional and behavioral difficulties in sixth grade. The study hypothesized that mother-to-infant bonding can mediate the long-term impacts of maternal depression on child mental health outcomes. Their findings were published online in the journal Archives of Women's Mental Health on April 15, 2025.

The study included 245 mother–child pairs from Okaya, Japan, with children born between April 2, 2009, and April 1, 2012. The team used the Edinburgh Postnatal Depression Scale (EPDS) and the Mother-to-Infant Bonding Scale-Japanese version (MIBS-J) to evaluate maternal depressive symptoms and bonding, respectively. Additionally, they measured child difficulties using the Japanese version of the Strengths and Difficulties Questionnaire (SDQ). The EPDS and MIBS-J data were collected from mothers approximately 2 weeks to 1 month postpartum during postnatal health checkups. Whereas the self- and parent-rated SDQ data were gathered from their sixth-grade children and their caregivers. Among the caregivers who completed the parent-rated SDQs, 92.2% were mothers, 7.3% were fathers, and one person was another caregiver.

Based on the collected data, 17.1% of mothers exhibited postpartum depressive symptoms, which aligned with the national prevalence rates in Japan. These symptoms showed both direct and indirect associations with mother-to-infant bonding and child difficulties. "Interestingly, it was found that mother-to-infant bonding mediated 34.6% of the effects of postpartum maternal depression on child difficulties, which confirmed the study's hypothesis," explains Dr. Sasayama. "Apart from these factors, the child's sex was a significant predictor of psychosocial difficulties, with boys showing higher total difficulty scores than girls, particularly in conduct and hyperactivity or inattention." However, both rating sources indicated greater difficulties among children whose mothers had postpartum depressive symptoms. These findings highlight the lasting impact of early bonding experiences between mother and child and their children's future psychosocial growth. This further emphasizes the need for early interventions targeting bonding in the context of maternal postpartum depression in order to promote healthy child outcomes. "Our findings help deepen our understanding of how early attachment experiences mediate the long-term impact of maternal mental health on children's emotional and behavioral outcomes. Future research should prioritize developing interventions that enhance postpartum mother-to-infant bonding as an approach to mitigate long-term psychosocial difficulties in children," adds Dr. Sasayama.

Future studies should also explore which specific depressive symptoms most affect bonding in larger sample populations and should include genetic data, socioeconomic factors, and other underlying mechanisms in shaping these associations to design targeted interventions to support affected mothers and their families.