Incidence of Postpartum Mental and Behavioral Disorders in Japan

OBJECTIVES: Postpartum depression (PPD) develops in a critical stage of a woman’s life and the likelihood of depressive symptoms could be twice as high as other periods of life. PPD is often left untreated and can continue for a long time. Negative impacts are expected on the subsequent family planning and the parenting behavior of the affected family. Thus, we assessed the incidence of postpartum mental and behavioral disorders, which can accelerate the already-falling birthrate in Japan.

METHODS: DeSC database including data of employee-based health insurance (EHI) for employees and their families and the citizens’ health insurance (NHI) for non-/self-employed workers was used. Since eutocia is not covered by the compulsory insurance and cannot be directly identified with claims, a childbirth was identified if a woman aged 15–49 years at childbirth had a matched ID with a newborn from April 2014 through May 2022. The cumulative incidence rate (CIR) of mental and behavioral disorders (F00–F99) were compared between the birth group and the non-birth control matched for sex, birthday month, insurance type, and the first and last month of the observable period using Logrank test. The monthly incidence from childbirth was also examined.

RESULTS: The birth group included 23,236 women (29% NHI, 3% EHI, 69% EHI as family members). The CIR was significantly higher in the birth group (p<0.0001). A total of 4,917 women developed mental and behavioral disorders in the birth group. The incidence was smaller during six months antepartum and larger during three months postpartum.

CONCLUSIONS: The incidence of mental and behavioral disorders was higher after the childbirth than before, suggesting the importance to pay attention to maternal mental health especially during three months after the childbirth even if no signs of PPD were observed before the childbirth.