Full-Term and Preterm Differences in Human Brain Functional Connectivity Development Across Birth

We possess a limited understanding of how preterm and full-term brains develop during the earliest stages of life, from the fetal to neonatal period, and how they respond to the birth transition. Here, we characterize brain resting-state functional connectivity (RSFC) using over 1000 longitudinal fetal and infant functional MRI scans from 21 to 52 post-conception weeks across birth. By mapping the developmental trajectory of RSFC across this window, we unveil marked divergences in developmental patterns between preterm- and term-born brains at both the global and network levels. When aligned by birth, the full-term group exhibit generally higher RSFC than the preterm group. For selected between-network connections with a significant prematurity effect, full-term cases demonstrate an overall increase in RSFC across age, whereas preterm cases show minimal change or even a decrease in connectivity of these systems. In contrast, when aligned by postconceptional age, the preterm group shows an accelerated increase in RSFC between 30 and 40 weeks. Across comparisons, mode of delivery and sex showed minimal influence on these trajectories. These findings offer novel insight into how prematurity and early exposure to the extrauterine environment alter the developmental trajectories of large-scale neural networks, advancing our understanding of both typical and preterm brain development.