Repeated screening links postpartum depression and bonding in Japanese cohort

Repeated screening during the first three months after childbirth identified distinct patterns of maternal depressive symptoms and mother–infant bonding difficulties in a Japanese hospital cohort. In the observational study, higher scores on the Edinburgh Postnatal Depression Scale were associated with higher scores on the Mother-to-Infant Bonding Scale, while trajectory analyses separated mothers into groups with improving, persistent, decreasing or increasing symptoms. The results suggest that one early assessment may not capture every mother’s changing experience, but the researchers cautioned that the study does not establish that screening improves outcomes or prevents maltreatment.

Associate Professor Takashi X. Fujisawa and Professor Akemi Tomoda of the Research Center for Child Mental Development at the University of Fukui led the research with Dr. Tomomi Yasaka of the Division of Developmental Higher Brain Functions at the United Graduate School of Child Development at Osaka University. They analyzed routine clinical records from 512 mother–infant dyads treated at a general hospital in Fukuoka City, Japan, between January 2013 and December 2018. The peer-reviewed study, “Maternal bonding difficulties and postpartum depression in pediatric clinical practice: a longitudinal study in a Japanese cohort,” appeared in Frontiers in Psychiatry on September 28, 2026.

Participants completed the Edinburgh Postnatal Depression Scale, or EPDS, at five days and at one, two and three months postpartum. The Mother-to-Infant Bonding Scale, or MIBS, was administered at one, two and three months. For the primary association analysis, the researchers used available paired observations for which both measures were present.

These included 807 observations from 509 mothers. Longitudinal statistical models assessed whether EPDS and MIBS scores were associated across the early postpartum assessment periods and whether that relationship changed over time. Higher EPDS total scores were significantly associated with higher MIBS total scores across the early postpartum period.

The analysis found neither a significant time effect nor a significant interaction between EPDS score and assessment time, indicating that the strength of the association did not significantly change across the measured periods. These findings identify a statistical association between depressive symptoms and bonding difficulties; they do not show that either condition causes the other. “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,” Fujisawa said.

The researchers next used exploratory trajectory-based analyses to examine whether mothers followed distinguishable patterns over time. Gaussian clustering identified the MIBS patterns, with the models producing the largest Bayesian information criterion, or BIC, among the alternatives considered. Among 77 mothers with complete MIBS data, three bonding-difficulty trajectories emerged: low-stable difficulties in 41 mothers, representing 53.2% of this complete-case subgroup; high-increasing difficulties in 22, or 28.6%; and moderate-decreasing difficulties in 14, or 18.2%.

Because the group sizes and percentages refer specifically to the 77 mothers with complete data, they should not be treated as population-wide prevalence estimates for all 512 mothers in the cohort. For depressive symptoms, full-information maximum-likelihood trajectory analysis included all 512 mothers and identified four patterns. The largest group was moderate-improving depression, assigned to 171 mothers, or 33.4% of the cohort.

A high-persistent pattern included 94 mothers, or 18.4%; a minimal-decreasing pattern included 86, or 16.8%; and a low-decreasing pattern included 161, or 31.4%. Membership in the MIBS and EPDS subgroup classifications showed a moderate association. In other words, the patterns measured by the two instruments were related, but they did not align perfectly in every mother, supporting the observation that depressive symptoms and bonding difficulties do not always follow the same course.

The high-increasing bonding-difficulty group was the trajectory that Fujisawa particularly emphasized. Its appearance in the longitudinal analysis demonstrates information that could be missed if bonding were assessed only once early after delivery. Its significance within the analysis lies in the observed worsening pattern across the first three postpartum months, not in a measured cause or a demonstrated downstream effect.

“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,” Fujisawa said. The findings offer a detailed picture of change during the months when both measures were collected. The EPDS patterns included symptoms that improved, remained high or decreased, while the MIBS analysis produced a group in which bonding difficulties increased.

The moderate association between trajectory memberships also means that neither instrument alone provided a complete substitute for the other in this sample. Repeated measurement produced a more differentiated view than a single score, while the observational design and exploratory subgroup analyses limit the conclusions that can be drawn from those patterns. Several limitations constrain the scope of the results.

The bonding trajectory analysis included only 77 mothers with complete MIBS data, compared with all 512 mothers included in the EPDS trajectory analysis. The authors also described the MIBS subgroup analysis as exploratory because it used a small, clinically selected complete-case sample. The study took place at a single hospital, so the results may not represent the experiences of mothers and infants treated in other settings or regions.

In addition, the observational design cannot determine whether depressive symptoms contribute to bonding difficulties, whether bonding difficulties contribute to depressive symptoms, or whether other factors influence both. The authors said the results support further prospective research and coordinated care involving pediatricians, midwives, public health nurses and mental health professionals. The clinical question is whether repeated assessment can help identify mothers who need additional support, consultation or referral to mental health services.

The present evidence establishes a significant association between the two measures, documents several distinct symptom trajectories and shows that some patterns became visible across repeated assessments. It does not demonstrate that repeated screening prevents maltreatment, improves child development or causes better family outcomes. The study therefore offers a prospective rationale for evaluating repeated assessment in pediatric care while leaving its clinical effectiveness to future research.

Subject of Research: Longitudinal patterns of postpartum depression and mother–infant bonding difficulties in a Japanese clinical cohort

Article Title: Tracking maternal depression and bonding may improve early support after childbirth

Article References: Tracking maternal depression and bonding may improve early support after childbirth. Original publication (Bibliographic details unavailable.)

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Keywords: postpartum depression, mother–infant bonding, repeated screening, maternal mental health, longitudinal cohort, trajectory analysis, pediatric care, Japanese hospital, observational study, Tracking, maternal, depression