Association Between Maternal Working Status and Unintentional Injuries Among 3 to 4-Month-Old Infants in Japan.

Objectives: Globally, unintentional injuries are one of the leading causes of infant death. Established risk factors for injuries during infancy include single parent households, socioeconomic disadvantage and maternal postpartum depression. We sought to examine whether maternal working status is associated with unintentional injury among infants in Japan.

Methods: We used data from an original questionnaire targeting mothers who participated in a 3 or 4-month health check-up program in Aichi prefecture, Japan. Experience of any type of unintentional injury was used as the primary outcome, and we also examined the experience of "falls" and "near-drowning" as secondary outcomes. We conducted multivariable logistic regression analysis, adjusting for covariates. We also performed propensity score matching in order to balance covariates between paid employment and unpaid employment groups.

Results: Among 6,465 valid responses (response rate, 67%), 9.8% of infants experienced unintentional injuries. After matching on propensity for maternal employment (based on 26 covariates), we found that infants of mothers in paid employment were 1.35 times (95% CI: 1.04-1.74) more likely to experience injures, including 1.60 times higher likelihood of falls (95% CI: 1.14-2.24). Near-drowning was not significantly associated with maternal employment. We also found that father's employment status was positively associated with risk of falls.

Conclusion: Both multivariable logistic analysis and propensity score matching analysis revealed that maternal paid employment status was associated with unintentional injuries among Japanese infants. To prevent infant injuries, comprehensive support for working families should be considered.