Association between maternal depressive symptoms and hair cortisol concentration during pregnancy with corpus callosum integrity in newborns

Maternal prenatal depressive symptoms are linked to neurodevelopmental impairments in offspring. Maternal cortisol levels are hypothesized to moderate this association, but its relationship with depressive symptoms is inconsistent. This study examined how maternal prenatal depressive symptoms and cortisol levels predict infant brain development, focusing on neonatal corpus callosum (CC) integrity. Using data from the FinnBrain Birth Cohort Study, we analyzed 37 mother-infant dyads. MRI data were collected from 2 to 5 weeks old infants, and DTI imaging estimated fractional anisotropy (FA) in CC regions (Genu, Body, and Splenium). Maternal cortisol levels were assessed through hair cortisol concentration (HCC) from a 5cm hair segment, reflecting cortisol over the last five months of pregnancy. A factor score of maternal depressive symptoms was computed from EPDS questionnaire data collected at gestational weeks 14, 24, and 34. We employed multivariate regression models with a Bayesian approach for statistical testing, controlling for maternal and infant attributes. Results indicated that maternal prenatal depressive symptoms and HCC interact negatively in predicting infants' FA across all CC regions. Infants exposed to high prenatal depressive symptoms and low HCC (1 SD below the mean) showed higher FA in all CC regions. These findings highlight the complex dynamics between maternal prenatal cortisol levels and depressive symptoms, revealing a nuanced impact of those factors on the structural integrity of infants' CC.