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.

Objectives: To evaluate the tracheal compression caused by the vascular ring in fetuses with double aortic arch (DAA) using prenatal ultrasound and to analyze the relationship between tracheal compression and postnatal clinical symptoms. Design: Retrospective cohort study. Setting: Two fetal medical centre in China. Population: 26 fetuses with DAA diagnosed with prenatal ultrasound and 334 singleton pregnancies with normal fetuses. Methods: The tracheal compression—evaluated by comparing the tracheal internal diameter Z-scores against the GA—was assessed in the fetuses with DAA and in normal fetuses. The live-born infants with DAA were divided into symptomatic and asymptomatic groups for the comparative analysis of Z-scores. Results: 26 fetuses with DAA were diagnosed and 14 (53.8%) fetuses with DAA were delivered alive. Among the 14 live-born infants, 7 (50.0%) were symptomatic while 7 (50.0%) were asymptomatic. The tracheal internal diameter Z-scores were significantly lower in the DAA group than in the normal groups (-0.6 [-1.0, -0.1] vs. 0.0 [-0.3, 0.3], P<0.001). Compared to the asymptomatic group, the tracheal internal diameter Z-scores were significantly lower in the symptomatic group (-1.5 [-1.8, -1.1] vs. -0.6 [-0.9, -0.1], P=0.018). Conclusions: The clinical symptoms in the infants with DAA were associated with prenatal tracheal compression, which can be prenatally evaluated using ultrasound. If fetuses are diagnosed with DAA, prenatal surveillance of the tracheal internal diameters and comparison with Z-score reference ranges could provide pertinent information that would aid perinatal clinical management.