Adaptive and maladaptive microstructural remodelling of the maternal brain revealed by diffusion kurtosis imaging

Postpartum depression (PPD) is a major maternal mental health concern that may arise during neurobiological and emotional adaptation. Alterations in these adaptive processes may contribute to depressive symptom vulnerability; however, the neurobiological basis of postpartum brain adaptation remains unclear. We investigated microstructural brain remodelling in postpartum women using diffusion kurtosis imaging (DKI) and evaluated its association with Edinburgh Postnatal Depression Scale (EPDS) scores. We compared brain magnetic resonance imaging findings between 15 women one month postpartum and 10 nulliparous women without psychiatric disorders. Tract-based spatial statistics and regions of interest were analysed using diffusion tensor and kurtosis metrics. Compared with nulliparous women, postpartum women showed significantly lower mean and axial diffusivity values in white matter regions, including the frontal lobe, basal ganglia, and corticospinal tract. The posterior insular cortex showed increased mean and radial kurtosis, whereas the putamen demonstrated decreased diffusivity. EPDS scores showed positive correlations with kurtosis metrics in the amygdala and negative correlations with diffusivity metrics in the hypothalamus. These findings suggest that the postpartum brain undergoes coordinated microstructural remodelling involving emotional regulation, stress response, and maternal behavioural adaptations. Thus, DKI may provide an objective neuroimaging biomarker for identifying maladaptive postpartum brain changes associated with depressive symptoms.