Association between infants' excessive crying and mother-infant bonding: a prospective observational study

This study aimed to determine the prevalence of excessive crying (EC) in Japanese infants and determine whether EC at two months postpartum is associated with mother-infant bonding at five months postpartum.

The participants were mothers aged 18 years or older who were hospitalised after the delivery of a full-term, singleton baby. They were recruited during their postpartum stay at a university hospital and were surveyed at two and five months postpartum using online questionnaires. The collected data were analysed using bivariate and multiple logistic regression analyses.

A total of 142 mothers agreed to participate and provided written informed consent; among them, 108 and 107 responded to the survey at two and five months postpartum, respectively. The prevalence of EC among the participants was 15.7% and 6.5% at two and five months of age, respectively. Multiple logistic regression showed that EC at two months and the Edinburgh Postnatal Depression Scale score at five months postpartum were associated with mother-infant bonding at five months postpartum (adjusted odds ratio [AOR]: 8.72, 95% confidence interval [CI]: 1.10-69.29; AOR: 1.49, 95% CI: 1.19-1.87, respectively).

This study is the first to show that EC at two months was associated with mother-infant bonding at five months postpartum. Mothers of infants exhibiting EC need continuous support, even after EC subsides.