Brain Growth Trajectories in Early-Onset Fetal Growth Restriction versus Appropriate- for Gestational-Age Fetuses: A Multicenter Prospective Longitudinal Study.

BACKGROUND: Despite the clinical importance of brain sparing in fetal growth restriction (FGR), current data on the specific patterns of brain growth trajectory in early-onset FGR (EO-FGR) remain sparse. METHODS: A multicenter prospective longitudinal study was conducted between November 2024 and February 2026. Three-dimensional tomographic ultrasound imaging was used to measure brain parameters in 36 pregnant women with EO-FGR and 36 with appropriate-for-gestational-age (AGA) fetuses at three time points: 26-28, 30-32, and 34-36 weeks of gestation. RESULTS: The EO-FGR group initially showed delayed growth in normalized cavum septi pellucidi length (CSPL') at GA 30-32 weeks compared with the AGA group, with values of 0.03 ± 0.001 and 0.03 ± 0.01, respectively (P-value = 0.007). Further significant reductions were observed in the EO-FGR group at a GA of 34-36 weeks in the CSPL' (0.03 ± 0.01 vs 0.04 ± 0.01, P-value < 0.001), normalized CSP width (0.03 ± 0.01 vs 0.03 ± 0.01, P-value < 0.001), and normalized occipitofrontal diameter (0.32 ± 0.09 vs 0.35 ± 0.01, P-value = 0.031). CONCLUSION: The cavum septi pellucidi and occipitofrontal diameter may serve as early structural indicators of brain growth trajectory in EO-FGR. However, larger cohort studies are needed to validate these findings and correlate them with post-natal imaging and long-term outcomes.