Perinatal Depression and Infant Mortality.

Importance: Perinatal depression is the most common maternal morbidity, but few US studies have examined whether perinatal depression is associated with infant mortality. Objectives: To examine the association between maternal depressive symptoms and infant mortality, assess heterogeneity by maternal and infant demographic and socioeconomic characteristics and risk factors, and explore heterogeneity across leading causes of infant mortality. Design, Setting, and Participants: This population-based retrospective cohort study used birth records from 2016 to 2020 linked to death records from 2016 to 2021 in New Jersey, which mandates screening for depressive symptoms in the immediate postpartum period. The cohort included singleton infants born in New Jersey between 2016 and 2020. Statistical analysis was performed between October 2025 and June 2026. Exposures: Edinburgh Postnatal Depression Scale score of 10 or higher, which indicated maternal depressive symptoms. Main Outcomes and Measures: The primary outcome was infant death within 364 days after birth. Adjusted relative risk (ARR) of infant death was estimated using log-link generalized linear models. Results: Among the 414 890 infants (212 760 males [51.3%]) with complete data included in the analysis, 413 984 (99.8%) did not die and 906 (0.2%) died. Their mothers had a mean (SD) age of 30.5 (5.7) years, and 63.0% were born in the US, 60.0% were privately insured, and 70.6% completed high school or college. The infant mortality rate was 7.2 per 1000 births for infants whose mothers had depressive symptoms and 2.0 per 1000 births for infants whose mothers did not have depressive symptoms. After statistical adjustment for covariates, the relative risk of death within 364 days after birth was higher for infants of mothers with depressive symptoms compared with infants of mothers without depressive symptoms (model 2: ARR, 2.89; 95% CI, 2.36-3.54). This association was consistent across maternal race and ethnicity, educational level, insurance status, and infant preterm birth. Associations were found between maternal depressive symptoms and infant deaths with these leading causes: prematurity-related conditions (ARR, 4.07; 95% CI, 2.82-5.87), perinatal conditions (ARR, 5.12; 95% CI, 3.39-7.73), congenital malformations and chromosomal abnormalities (ARR, 3.56; 95% CI, 2.14-5.94), and sudden infant death syndrome (ARR, 2.08; 95% CI, 1.11-3.89). Conclusions and Relevance: In this cohort study, infants born to mothers with depressive symptoms had a higher risk of death before 1 year of age compared with infants whose mothers had no depressive symptoms. Expanding maternal depression screening and interventions for individuals with depressive symptoms is critical for improving maternal and infant health.