Functional gradient alteration and structural remodeling in postpartum women

• First demonstration of contracted functional connectome gradient topography in postpartum women (PW), revealing large-scale cerebral functional and structural reorganization • Gray matter reductions in PW mediate functional connectome gradient reorganization through altered network integration/segregation properties • Large-scale functional connectome gradient changes correlate with clinical symptoms (sleep quality and anxiety) Postpartum women (PW) undergo profound brain functional and structural reorganization to support maternal adaptation. However, the specific large-scale neural adaptation mechanisms remain unclear. The current study employed a multimodal MRI approach integrating functional gradient analysis, graph-theoretical network metrics, and morphometry to explore the brain connectome reorganization across the postpartum period and its clinical correlates in 209 participants (134 PW and 75 healthy nulliparous women (HNW)). Compared to HNW, PW exhibited a significant contraction of the first two principal functional gradients, reduced local network segregation and less efficient information processing, accompanied by matter volume (GMV) reductions. Mediation analysis revealed that GMV alterations in PW modulate functional gradient reorganization by influencing network integration and segregation. These neural changes were closely linked to clinical symptoms including sleep quality and anxiety. Our findings revealed a large-scale network reconfiguration in PW, simultaneously elucidating neurobiological mechanisms of adaptive plasticity in postpartum period.