Hum Brain Mapp. 2026 Sep;47(13):e70608. doi: 10.1002/hbm.70608.
ABSTRACT
The postpartum period involves substantial brain changes, but whether these represent pathological aging or adaptive plasticity remains unclear. We applied machine learning-based brain age prediction to quantify postpartum brain aging trajectories in a controlled longitudinal study. Brain age gap, the difference between MRI-predicted and chronological age, was assessed in 55 women (25 postpartum and 30 nulliparous controls). Postpartum women were assessed at approximately 3 and 12 months postpartum; controls were assessed at matched intervals. Postpartum women showed elevated brain age gap at 3 months (2.5 ± 2.7 years) compared with controls (0.3 ± 3.6 years; p = 0.01, Cohen’s d = 0.69), which normalized by 12 months. Within-group analysis revealed significant brain age gap decrease in postpartum women (-3.3 ± 3.5 years; p = 0.008), while controls showed minimal change; the between-group difference in longitudinal change did not reach statistical significance (p = 0.12, Cohen’s d = -0.58). Across all participants, brain age gap correlated with working memory performance (ρ = -0.30; p = 0.03), depressive symptoms (ρ = 0.38; p = 0.004), and subjective cognitive complaints (ρ = 0.28; p = 0.04) at baseline, providing preliminary evidence of clinical relevance. Explainability analysis using Shapley additive explanations identified subcortical structures as the network most selectively associated with the postpartum elevation in brain age gap at 3 months (p = 0.006, Cohen’s d = 0.82), with normalization by 12 months. Together, these findings indicate transient brain age gap elevation in postpartum women without statistical confirmation of a trajectory differing from controls. With brain age gap providing a quantitative index of postpartum brain structural change, these preliminary findings are consistent with adaptive neuroplasticity, suggesting that such change may be temporary rather than reflecting permanent impairment.
PMID:42675020 | DOI:10.1002/hbm.70608
