Discrete category of mother-to-infant bonding disorder and its identification by the Mother-to-Infant Bonding Scale: A study in Japanese mothers of a 1-month-old.

BACKGROUND

Difficulty of maternal bonding towards a baby is widely recognised. It is unclear whether this phenomenon is dimensional or categorical. If categorical, an optimal cut-off score of a screening instrument is needed in clinical settings.

AIMS

In this study, we investigated whether maternal bonding is dimensional or categorical phenomenon and try to set optimal cut-off score of screening instruments.

METHODS

Self-report questionnaire studies were conducted in a general hospital and four antenatal clinics. Two-step cluster analysis was conducted for the Mother-to-Infant Bonding Scale (MIBS) subscale scores in 723 mothers of neonates. ROC curves and optimal cut-off points of the MIBS scores were calculated based on cluster-analysis derived groups.

RESULTS

A 2-cluster structure appeared: "normal" (n=619) vs. "pathological maternal bonding" (n=104). Mothers of the latter category scored significantly higher in terms of postnatal depression and neonatal abuse than those of the former category. AUC of the ROC curve by the total MIBS scores both 5days and 1month after childbirth were >0.9. The optimal cut off scores were 3/4 at 5days, and 4/5 at 1month, after childbirth.

CONCLUSIONS

There was a group of mothers with high MIBS scores discretely different from those with low MIBS scores. MIBS may be a useful tool to identify mothers with a severe bonding disorder that needs clinical intervention.