Japanese study links postpartum depression to mother-infant bonding difficulties

A Japanese study found that higher postpartum depression scores were associated with greater mother–infant bonding difficulties. Repeated assessments identified varied symptom patterns, including mothers whose bonding difficulties increased during the first three months. The findings suggest that pediatric teams may benefit from monitoring maternal depressive symptoms and bonding repeatedly, rather than relying on a single early assessment, to recognize mothers who may need closer support, consultation, or referral to mental health services.

Postpartum depression and difficulties forming an emotional bond with the infant can affect maternal well-being and child development, yet the two problems do not always follow the same course. A single assessment may miss mothers whose bonding difficulties persist or increase after childbirth. To explore these patterns in routine pediatric care, researchers examined repeated measures of depressive symptoms and mother–infant bonding during the first three months after delivery in a Japanese clinical cohort.

Addressing this challenge, a research team was led by Associate Professor Takashi X. Fujisawa and Professor Akemi Tomoda from the Research Center for Child Mental Development at the University of Fukui, Japan, along with Dr. Tomomi Yasaka from the Division of Developmental Higher Brain Functions at the United Graduate School of Child Development, Osaka University, Japan. The team analyzed records from 512 mother–infant dyads from a general hospital in Fukuoka City between January 2013 and December 2018. Mothers completed the Edinburgh Postnatal Depression Scale (EPDS) at five days and one, two, and three months postpartum, and the Mother-to-Infant Bonding Scale (MIBS) at one, two, and three months. Their findings were published on September 28, 2026, in Volume 17 of the journal Frontiers in Psychiatry.

The analysis included 509 mothers who contributed 807 paired observations. Using all available paired observations, the researchers found that higher EPDS total scores were significantly associated with higher MIBS total scores across the early postpartum period. The researchers also found no significant time effect or EPDS-by-time interaction, suggesting that the strength of the association did not significantly change across the assessment periods.

"Our findings indicate that depressive symptoms and bonding difficulties are closely connected during the early postpartum period, but the relationship should not be interpreted as proof that one causes the other," says Dr. Fujisawa.

The researchers then explored whether mothers followed different patterns over time. Among 77 mothers with complete MIBS data, analyses identified three exploratory trajectory-based patterns: low-stable bonding difficulties in 41 mothers (53.2%), high-increasing difficulties in 22 (28.6%), and moderate-decreasing difficulties in 14 (18.2%). For EPDS, FIML-based trajectory analysis of 512 mothers identified four patterns: moderate-improving depression in 171 mothers (33.4%), high-persistent depression in 94 (18.4%), minimal-decreasing depression in 86 (16.8%), and low-decreasing depression in 161 (31.4%). MIBS and EPDS subgroup membership showed a moderate association.

"The increasing bonding-difficulty pattern is particularly important to recognize because it shows why repeated contact can provide information that an early assessment alone may miss," says Dr. Fujisawa.

Overall, the study suggests that repeated assessment of maternal depressive symptoms and bonding during pediatric visits may help clinicians recognize mothers who need additional support. The authors emphasize that the trajectory findings are exploratory because the MIBS subgroup analysis involved a small, clinically selected complete-case sample, and the study was conducted at a single hospital. The findings therefore do not establish causality or demonstrate that screening prevents maltreatment. Instead, they support further prospective research and coordinated care involving pediatricians, midwives, public health nurses, and mental health professionals to determine whether repeated assessment can improve support for mothers and children.