Contribution of Parenting Factors to the Developmental Attainment of 9-Month-Old Infants: Results From the Japan Children’s Study

BACKGROUND: Child development integrates several interdependent domains, but few studies have attempted to identify the common factors that contribute to these different domains of development in infancy. The aim of the present study was to identify the factors that contribute to several domains of developmental attainment in 9-month-old infants. METHODS: We used data from the Japan Children’s Study, a prospective cohort study underway in Japan since 2005. Mothers completed questionnaires about their children’s temperament, coparenting behaviors, maternal parenting stress, and parenting behavior. The Kinder infant development scale was used to evaluate child development outcomes. RESULTS: A total of 270 children were included in this analysis. After adjusting for the children’s birth weight, gestational age, temperament, and other family environmental variables, multiple logistic regression analyses showed that greater maternal cognitive stimulation was associated with the development of receptive language, expressive language, social relationships, and feeding. Results also suggest that early supportive coparenting helped to promote development in manipulation, receptive language, and social relationships. Maternal parenting stress was stable between the infant ages of 4 and 9 months and was negatively correlated with scores for coparenting and maternal stimulation, which suggests an indirect effect of maternal parenting stress on child outcomes. CONCLUSIONS: Supportive coparenting and maternal cognitive stimulation were the most important contributors to most domains of child development. Our findings suggest that educational interventions targeting young families would help parents establish and maintain an environment of successful coparenting and cognitive stimulation as their children grow.