Although there is some evidence regarding an association between maternal bonding disorder and child development, studies have mainly focused on development during the period of infancy. We aimed to examine the associations between maternal postnatal bonding disorder and developmental delays in children beyond 2 years of age. We analyzed data from 8380 mother-child pairs who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Maternal bonding disorder was defined as Mother-to-Infant Bonding Scale score of ≥5 at 1 month after delivery. The Ages & Stages Questionnaires, Third Edition, which consists of five developmental areas, was used to assess developmental delays in children at 2 and 3.5 years of age. Multiple logistic regression analyses were conducted to examine the associations between postnatal bonding disorder and developmental delays after adjustment for age, education, income, parity, feelings toward pregnancy, postnatal depressive symptoms, child\'s sex, preterm birth, and birth defects. Bonding disorder was associated with developmental delays in children at 2 and 3.5 years of age: the odds ratios (95% confidence intervals) were 1.55 (1.32-1.83) and 1.60 (1.34-1.90), respectively. Bonding disorder was associated with delay in communication only at 3.5 years of age. Bonding disorder was associated with delay in gross motor, fine motor, and problem solving, but not delay in the personal-social domain, at 2 and 3.5 years of age. In conclusion, maternal bonding disorder 1 month after delivery was associated with an increased risk of developmental delays in children beyond 2 years of age.

Although there is evidence that maternal perinatal mental disorders are associated with emotional/behavioral problems in children, the long-term impacts of postnatal bonding disorder remain unclear. We aimed to examine the associations between maternal postnatal bonding disorder and emotional/behavioral problems in preschool children.
We analyzed data from 7220 mother-child pairs who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Maternal bonding disorder was defined as Mother-to-Infant Bonding Scale score ≥5 at 1 month after delivery. The Child Behavior Checklist for Ages 1½-5 was used to assess emotional/behavioral problems, and its subscales were used to assess internalizing and externalizing problems in children at 4 years of age. Multiple logistic regression analyses were conducted to examine the associations of postnatal bonding disorder with emotional/behavioral, internalizing, and externalizing problems after adjustment for age, education, income, parity, prenatal psychological distress, postnatal depressive symptoms, child\'s sex, preterm birth, and birth defects.
The prevalence of postnatal bonding disorder was 14.8 %. Postnatal bonding disorder was associated with an increased risk of emotional/behavioral problems in children: the odds ratio (OR) was 2.06 (95 % confidence interval [CI], 1.72-2.46). Postnatal bonding disorder was also associated with increased risks of internalizing problems and externalizing problems in children: the ORs were 1.69 (95 % CI, 1.42-2.02) and 1.90 (95 % CI, 1.59-2.26), respectively.
Bonding and problems were self-reported.
Bonding disorder at 1 month after delivery was associated with an increased risk of emotional/behavioral problems in children at 4 years of age.

Although there is substantial information about the effects of social relationships on mental health, their effects on postnatal bonding remain unclear. We aimed to examine the association between social isolation and postnatal bonding disorder. We analyzed data from 17,999 women who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. An abbreviated version of the Lubben Social Network Scale was used to assess social isolation in the second trimester of pregnancy, and its subscales were used to assess marginal family ties and marginal friendship ties. Bonding disorder was defined as a Mother-to-Infant Bonding Scale score of ≥ 5 1 month after delivery. Multiple logistic regression analyses were conducted to examine the association between social isolation and postnatal bonding disorder after adjusting for age at delivery, parity, feelings towards pregnancy, psychological distress during pregnancy, and household income. Analyses stratified by postnatal depressive symptoms (PDS) were also conducted. Social isolation was associated with postnatal bonding disorder: the odds ratio (OR) was 1.55 (95% confidence interval [CI], 1.41-1.71). Marginal family ties and friendship ties were associated with postnatal bonding disorder: the ORs were 1.40 (95% CI, 1.23-1.60) and 1.44 (95% CI, 1.32-1.57), respectively. Marginal family ties were associated with postnatal bonding disorder only among women without PDS: the ORs were 1.30 (95% CI, 1.10-1.55) among women without PDS and 1.13 (95% CI, 0.91-1.40) among women with PDS. Social isolation during pregnancy was associated with an increased risk of postnatal bonding disorder.

Despite much knowledge of the effects of maternal psychopathology on bonding, the effects of personality have received less attention. We aimed to examine the association between maternal personality and postnatal bonding disorder.
We analyzed data from 15,654 women who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Personality was assessed in middle pregnancy using the short-form Eysenck Personality Questionnaire-Revised, with the score for each subscale categorized into four levels. Bonding disorder was defined as the Mother-to-Infant Bonding Scale score of ≥5 one month after delivery. Multiple logistic regression analyses were conducted to examine the association between personality and bonding disorder after adjusting for age, education, parity, feelings towards pregnancy, social isolation, as well as the Edinburgh Postpartum Depression Scale (EPDS) score.
Higher extraversion was associated with a decreased risk of bonding disorder (p for trend <0.001). Higher neuroticism was associated with an increased risk of bonding disorder (p for trend <0.001), and this association disappeared after further adjustment for EPDS score (p for trend 0.39). No association between psychoticism and bonding disorder was observed (p for trend 0.83), and the association appeared after further adjustment for EPDS score (p for trend 0.0017). Higher lie was associated with a decreased risk of bonding disorder (p for trend <0.001).
Maternal personality and bonding were self-reported.
Lower extraversion, higher psychoticism, and lower lie were associated with bonding disorder. The association between higher neuroticism and bonding disorder was explained by postnatal depressive symptoms.