Effect of 2-week postpartum check-ups on screening positive for postpartum depression: a population-based cohort study using instrumental variable estimation in Japan

Background: Postpartum depression is experienced by approximately 10% of women and affects the health and development of their children. Although it is recommended that all mothers have the opportunity for early detection and intervention for postpartum depression, it is unclear whether early postpartum check-ups help to reduce postpartum depression.
Objective: The aim of this study was to assess the effect of 2-week postpartum check-ups on screening positive for postpartum depression in Japan.
Methods: This was a population-based cohort study that used the administrative database of Tsuyama, Japan. Participants were women who received postpartum home visits from a public health nurse in Tsuyama during the fiscal years 2017–2019. Data were obtained on participant’s attendance at a 2-week postpartum check-up and their responses on the Edinburgh Postpartum Depression Scale. Owing to the initiation of a publicly funded postpartum check-up programme, participants were pseudo-randomly assigned to receive/not receive a 2-week postpartum check-up. We conducted instrumental variable estimation to assess the causal effects of the check-up on screening positive for postpartum depression.
Results: The characteristics of the 1,382 participants did not differ by fiscal year of childbirth. We found a 6.7% (95% confidence interval 2.2–11.2) reduction in the prevalence of screening positive for postpartum depression as an effect of 2-week postpartum check-ups among women received 1-month postpartum home visits.
Conclusion: The results suggest that 2-week postpartum check-ups are effective in reducing the prevalence of screening positive for postpartum depression among 1-month postpartum women. Despite some limitations, early postpartum care could reduce postpartum depression.