Associations between broader autism phenotype (BAP) and maternal attachment are moderated by maternal postpartum depression when infants are one month old: A prospective study of the Japan environment & children's study

Background: Broader autism phenotype (BAP) refers to the expression of behavioral and cognitive dispositions similar to autism spectrum disorder. The present study investigated whether mothers' BAP was prospectively associated with maternal attachment, and if postpartum depression modified this association. Methods: The Japan Environment and Children's Study (JECS) is a national and government-funded birth cohort study that began in January 2011. Among the 103,099 mothers enrolled, 87,369 mothers without a history of depression were included in the analysis. Self-administered questionnaires were used. These included: the Japanese version of the Autism Spectrum Quotient, the Mother to Infant Bonding Scale, and the Edinburgh Postnatal Depression Scale. Logistic regression analyses were performed. Results: The BAP during the second or third trimester of pregnancy was linearly associated with an increased risk of postpartum depression and insecure maternal attachment when infants were one month old (p for trend < 0.001), after adjusting for confounding variables. When stratified by postpartum depression, among the BAP subscales, deficiencies in social skills and communication were associated with an increased risk of insecure maternal attachment in mothers without postpartum depression. The relationships between the BAP subscales and maternal attachment were attenuated among mothers with postpartum depression. Limitations: Only five items of the Mother to Infant Bonding Scale were used in the present study, and thus the results should be interpreted with caution. Conclusions: Mothers' BAP was predictive of insecure maternal attachment toward their infant. Postpartum depression partially moderated the associations between mothers' BAP and insecure maternal attachment.