Frontal Lobe Development in Fetuses with Growth Restriction: A Case-Control Study

Objective: To evaluate the impact of fetal circulatory redistribution (FCR) on frontal lobe development in fetuses with growth restriction (FGR) compared with appropriately grown fetuses. Design: Case-control study Setting: A referral center from August 2020 to July 2021. Population/Sample: 324 appropriately grown fetuses were included to establish Z-score reference ranges for frontal antero-posterior diameter (FAPD) and occipito-frontal diameter (OFD). The case-control analyses included 55 with FGR and 220 gestational age and fetal sex-matched appropriately grown fetuses. Methods: FAPD and OFD were measured on trans-ventricle view in FGR and appropriately grown fetuses. Main Outcome Measures: We calculated Z-scores for FAPD and OFD in appropriately grown fetuses. To compare intracranial parameters, we randomly selected a control group of appropriately grown fetuses matched with the FGR group at ultrasonography. We performed between-group comparisons of FAPD Z-score, OFD Z-score, and FAPD/OFD ratio. Results: All independent variables (GA, BPD, FL, and TCD) were strongly correlated with FAPD and OFD. FAPD/OFD ratio was curvilinear related to all the independent variables (GA, BPD, FL, and TCD). Compared with appropriately grown fetuses, fetuses with FGR showed a significantly lower FAPD/OFD ratio and FAPD Z-score. There was no significant difference in the FAPD Z-score and FAPD/OFD ratio between fetuses with FGR with and without FCR. Conclusions: The FAPD/OFD ratio slightly varied during pregnancy, with a small reduction before and an increase after about 33 gestational weeks. Fetuses with FGR showed impaired frontal lobe growth; moreover, fetal frontal lobe development disorders were not significantly different in FGR with FCR.