Risk of postpartum depression and very early child mistreatment among mothers reporting higher autistic traits: Evidence from the Japan Environment and Children's Study.

Abstract Background Little is known about how mothers who report higher autistic traits face new parenthood. This study examined the association between antenatal non-clinical autistic traits and the risks of both postpartum depression (PPD) and child mistreatment at one-month postpartum and if these associations were mediated by preexisting social support. Methods Participants included 73,532 singleton mothers without histories of psychiatric conditions from the Japan Environment and Children's Study, a nationwide birth cohort. Autistic traits were measured during the second/third trimesters using the short-version of the Autism Quotient-Japanese version. Participants were classified into three groups (i.e., typical-range, moderate-range, and high-range). PPD was measured using the Japanese version of the Edinburgh Postnatal Depression Scale, while participants self-reported experiences of child mistreatment (i.e., hit or shake the child); both assessments were conducted at one-month postpartum. Individual social support was reported during pregnancy. Data analyses were conducted through Poisson regressions. Results A total of 7,147 (9.7%) participants reported PPD, while 12,994 (17.7%) reported child mistreatment at one-month postpartum. Autistic traits were associated with increased PPD risk (adjusted-relative risk [aRR] =1.74, 95%CI=1.64–1.84 for moderate-range; aRR=2.33, 2.13–2.55 for high-range) and child mistreatment (aRR=1.19, 1.13–1.24 for moderate-range; aRR=1.39, 1.28–1.50 for high-range) independently of confounders. Social support mediated 26–31% of these associations for moderate/high-range groups (both risks). Limitations Self-reported measurements were used. Conclusions Mothers who reported moderate-to-high autistic traits in the general population were vulnerable to PPD and newborn mistreatment at one-month postpartum, which was partially explained by the lack of social support during pregnancy.