Measurement at first time point.
The biometry of the fetal brain (BPD, FOD and TCD) and skull (BPD and FOD) was not different between fetuses with CDH and those without. The extra axial space and atrial width in CDH fetuses were within the normal range, except for one fetus having mild ventriculomegaly (11 mm). The total brain cortical grading for fetuses with CDH was significantly lower than in controls (p<0.003). (Figure 3) When comparing the brain grading of each hemisphere, the difference was present on both sides (both p<0.003). The opercularization was delayed on the left side (p=0.011), but not on the right (p=0.057). There was a reduced depth of the parieto-occipital fissure (p<0.003 on the right and p=0.003 on the left), cingulate fissure (left and right p<0.003) but the depth of the calcarine fissure was normal on both sides (p>0.05) compared with controls. The Sylvian fissure was only just significantly deeper on the right (p=0.042), but not on the left (p=0.055) in fetuses with CDH. The insular depth in fetuses with CDH was within the normal range (p>0.05). There was no difference in volume of the total skull, extra-axial space, ventricular system, white matter or cerebellum between CDH fetuses and normal controls. (table S2)