Association of prenatal noise exposure with postpartum depressive symptoms and self-harm ideation

Abstract

Environmental noise is a pervasive but understudied determinant of perinatal mental health. We investigated whether prenatal residential noise exposure was associated with postpartum depressive symptoms and clinically documented self-harm ideation, thereby extending evidence beyond antenatal symptoms to clinically important postpartum outcomes. This dual-center cohort included 1,687 pregnant women recruited in urban and suburban Shanghai between 2019 and 2022. modeled residential outdoor noise level was estimated at 50 × 50 m resolution using a Shanghai-specific land-use regression model. Postpartum depressive symptoms were defined inclusively as an Edinburgh Postnatal Depression Scale score ≥ 10 at 35–49 days postpartum or qualifying electronic health record (EHR) diagnosis/antidepressant evidence within six months after delivery. Self-harm ideation was identified from postpartum EHR documentation. Modified Poisson models estimated adjusted risk ratios (aRRs) per 3.66 dB increase, with restricted cubic splines used to explore nonlinearity. Among 1,687 participants, 370 (21.9%) met the postpartum depressive symptom outcome and 95 (5.6%) had documented self-harm ideation. In primary linear analyses, noise was not clearly associated with postpartum depressive symptoms (aRR 1.03, 95% CI 0.92–1.14) and showed a positive but imprecise association with self-harm ideation (aRR 1.23, 95% CI 0.98–1.54). For postpartum depressive symptoms, the test for nonlinearity was nominally significant ( P-nonlinear = 0.049 ), but the overall spline association was not ( P-overall = 0.143 ); post hoc range analyses did not provide formal evidence of a change in slope. Results were broadly robust across alternative outcome definitions and sensitivity analyses. Primary analyses did not show a clear linear association between prenatal residential noise and postpartum depressive symptoms, although modest associations cannot be excluded. The nominal evidence of nonlinearity for the depressive-symptom outcome and the positive but imprecise self-harm estimate are hypothesis-generating and warrant independent evaluation.