Maternal personality and postnatal bonding disorder in Japan: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

Highlights

• We examined the association between maternal personality and postnatal bonding.

• Lower extraversion was associated with postnatal bonding disorder.

• The association between neuroticism and bonding was explained by depression.

• Higher psychoticism was associated with postnatal bonding disorder.

• Lower lie was associated with postnatal bonding disorder.

Abstract

Background

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.

Methods

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.

Results

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).

Limitations

Maternal personality and bonding were self-reported.

Conclusions

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.

Introduction

The formation of mother–to–infant bonding —maternal feelings and emotions towards her infant—has been a central focus of obstetric, neonatal, and pediatric nursing care (Bicking Kinsey and Hupcey, 2013). Postnatal bonding disorder has potentially serious effects on the long-term mother–child relationship, including child abuse or neglect (Brockington, 1996). In addition, disordered mother–child relationships are associated with poorer children's neuropsychological, behavioral, emotional, and social development from infancy to adulthood (Behrendt et al., 2019). Therefore, it is important to investigate the factors associated with bonding disorder to early identify and support mothers at higher risk for bonding disorder.

Despite the wealth of knowledge on the effects of maternal psychopathology, such as depressive symptoms, on bonding (Tichelman et al., 2019), the effects of maternal personality have received less attention. Maternal personality—individual differences in characteristic patterns of thinking, feeling and behaving—is associated with postnatal depressive symptoms (Iliadis et al., 2015), parenting style (Prinzie et al., 2009), and child psychological development (Landi et al., 2020). In contrast, there is limited evidence on the association between maternal personality and postnatal bonding disorder. Low persistence, low self-directedness, low cooperativeness (Ohashi et al., 2014), pessimism (Robakis et al., 2015), dysfunctional perfectionism and avoidant personality style (Oddo-Sommerfeld et al., 2016), emotion regulation difficulties (Behrendt et al., 2019), anger trait (Kitamura et al., 2015), and broader autism phenotype (Hirokawa et al., 2019) were predictive of postnatal bonding disorder. These existing studies focused on different personality dimensions anchored in diverse personality models, making the generalization of the results more difficult. Extraversion and neuroticism are two key personality dimensions that have been studied most intensively, as they are shared by different factor models of personality (Digman, 1990). However, to the best of our knowledge, extraversion has not been studied in the context of postnatal bonding, and only one study examined the association between neuroticism and postnatal bonding (Handelzalts et al., 2019). One meta-analytic review examining the associations between parents’ personality and parenting demonstrated that higher extraversion, agreeableness, and conscientiousness, and lower neuroticism were associated with more warmth and behavioral control (Prinzie et al., 2009). Therefore, we hypothesize that these dimensions of maternal personality are associated with postnatal bonding disorder.

Considering the above circumstances, we aimed to examine the associations between maternal personality and postnatal bonding disorder. Extraversion, neuroticism, psychoticism, and lie were used as personality dimensions, which were the subscales of the Eysenck Personality Questionnaire-Revised (EPQ-R) (Eysenck and Eysenck, 1975; Eysenck et al., 1985). As the association between personality and bonding was suggested to be mediated by postnatal depressive symptoms (Oddo-Sommerfeld et al., 2016; Handelzalts et al., 2019), we also focused on the effects of postnatal depressive symptoms on the association with bonding.