Corpus callosum and subarachnoid space measurements in fetuses with congenital heart disease: a prospective case-control study.

PURPOSE: This study investigated the associations of prenatally diagnosed congenital heart disease (CHD) with head circumference (HC) and supratentorial brain structures, specifically the corpus callosum (CC) and subarachnoid space (SAS), and determined whether these measurements varied according to expected fetal brain oxygen delivery. METHODS: This prospective case-control study included 102 pregnancies at 32 to 36 weeks of gestation: 51 fetuses with CHD and 51 healthy controls. CHD cases were grouped according to expected fetal brain oxygen delivery as class A (n=26, reduced supply) or class B (n=25, normal supply). Measurements included CC length, the heights of the genu, body, and splenium, SAS, and HC. RESULTS: Gestational age at delivery and birth weight were significantly lower in the CHD group than in controls (both P<0.01). Total CC length and all segmental heights (genu, body, and splenium) were significantly reduced in both CHD subgroups (class A and class B) compared with healthy controls (all P<0.01). However, no significant differences in CC parameters were observed between class A and class B (P>0.99). SAS (P=0.267) and HC (P=0.083) measurements did not differ significantly among the three study groups. CONCLUSION: Fetuses with CHD exhibited significant structural reductions across all CC dimensions, independent of the expected cerebral oxygen delivery pattern, whereas global parameters (HC and SAS) did not differ significantly. These findings suggest that CHD-related prenatal brain alterations may involve white matter development even without measurable changes in global cranial parameters, supporting CC biometry as a potentially sensitive marker for early neurodevelopmental risk assessment.