The prevalence and risk factors for postpartum depression symptoms of fathers at one and 6 months postpartum: an adjunct study of the Japan Environment & Children's Study

Objective: To survey prevalence and risk factors for paternal postpartum depression symptoms at one and 6 months postpartum in Japan.Material and methods: The study participants enrolled in the prospective birth cohort study of an adjunct study of the Japan Environment and Children's Study. Postpartum depression symptoms were evaluated using the Japanese version of the Edinburgh Postnatal Depression Scale (EPDS-J). The cut-off scores on the paternal EPDS-J were eight and on maternal EPDS-J was nine, respectively. The multivariate logistic regression included an adjustment for paternal age, maternal age, the number of children in the family, family structure, paternal employment, paternal academic history, household income, paternal smoking status, paternal history of mental health disorders, the Kessler 6-item psychological distress scale (K6) score during pregnancy, infertility treatment, paternal mental intimate partner violence (IPV) during pregnancy, paternal physical IPV during pregnancy, the sex of the newborn, congenital anomalies of the newborn, infant disease under medical treatment, returning to the maternal parent's house to give birth or take care of infant, the father's history of disease or injury that required medical treatment, paternity leave, and the EPDS-J for mothers.Results: A total of 1023 and 1330 fathers and their spouse who had a single delivery were assessed at one and 6 months postpartum, respectively. The prevalence of paternal EPDS-J scores ≥8 was 11.2 and 12.0% at one and 6 months postpartum, respectively. In the multiple logistics analysis, paternal EPDS-J scores ≥8 at 1 month postpartum was significantly associated with history of mental health disorders (adjusted odds ratio (AOR) 2.825; 95% confidence interval (CI): 1.047-7.623), K6 score ≥13 during pregnancy (AOR 4.116; 95% CI: 1.598-10.599), household income <4000 × 10³ yen (AOR 1.799; 95% CI: 1.072-3.021), and infant disease under medical treatment (AOR 1.720; 95% CI: 1.015-2.915). Paternal EPDS-J scores ≥8 at 6 months postpartum was significantly associated with K6 scores ≥13 during pregnancy (AOR 4.621; 95% CI: 2.113-10.107), unemployment (AOR 3.751; 95% CI: 1.739-8.091) and maternal EPDS-J scores ≥9 (AOR 2.460; 95% CI: 1.514-3.996).Conclusion: The prevalence of paternal postpartum depression symptoms were 11.2 and 12.0% at one and 6 months postpartum. Paternal postpartum depression symptoms at 1 month postpartum were associated with the history of mental health disorders, psychological distress during pregnancy, low income, and infant disease under medical treatment. Paternal postpartum depression symptoms at 6 months postpartum were associated with psychological distress during pregnancy, unemployment, and maternal postpartum depression. It is important to consider the paternal postpartum depression symptoms, and further enlightenment regarding these issues is recommended in Japan.