Association Between Maternal Postpartum Depression and Unintentional Injury Among 4-Month-Old Infants in Japan

Objectives Unintentional injury among infants is a major public health issue; however, the relationship between unintentional infant injury and postpartum depression remains unclear. In this study, we aim to investigate the association between the two. Methods We administered an original questionnaire to mothers participating in a 3- or 4-month health check-up program (target n = 9707). This questionnaire assessed infant health, including types of unintentional injury experiences used in previous study, and maternal mental health such as postpartum depression, by the validated screening tool, the Edinburgh Postnatal Depression Scale (EPDS). Associations between infant injury and postpartum depression were assessed using logistic regression adjusted for covariates, including parental, infant, and household characteristics. Results In total, 6534 women responded to the questionnaire with valid answers on the EPDS (valid response rate, 67 %). Of the sample, 9.8 % of infants experienced unintentional injury (fall: 5.6 %; near-drowning: 1.2 %), and 9.5 % of mothers had postpartum depression (EPDS score of 9+). After adjusting for covariates, postpartum depression was significantly positively associated with any unintentional injury (odds ratio [OR] 1.59, 95 % confidence interval [CI] 1.24-2.04), and falls (OR 1.41, 95 % CI 1.02-1.95), although near-drowning was not significantly associated. Conclusion Postpartum depression might be a risk factor for unintentional injury of infants aged up to 4 months. Further prospective studies are needed to confirm the association between postpartum depression and unintentional injury of infants.