Middle Cerebral Artery Peak Systolic Velocity in Fetuses With Transposition of the Great Arteries

Objective To examine peak systolic velocity in the middle cerebral artery (MCA‐PSV) in fetuses with transposition of the great arteries (TGA) and evaluate if TGA is associated with fetal anemia. Method A retrospective, exploratory study with inclusion of singleton fetuses born with TGA at Copenhagen University Hospital Rigshospitalet 2016–2023. Data on MCA‐PSV, neonatal hemoglobin and specific diagnoses were manually retrieved from patient files. Results In 52 cases, 205 MCA‐PSV measurements from GA 20 + 0 to 39 + 1 met the inclusion criteria. Overall median MCA‐PSV MoM was 1.09 (IQR 0.96; 1.20), increasing from 0.97 (IQR 0.86; 1.15) at gestational week 20 + 0 to 24 + 6 to 1.13 (IQR 0.95; 1.19) at gestational week 35 + 0 to 39 + 1. There were no differences in MCA‐PSV MoM between cases with and without surgical closure of a VSD. Median hemoglobin concentration was 16.4 g/dL (IQR 15.3–17.2 g/dL) and MCA‐PSV was inversely correlated with hemoglobin (−4.81 [95% confidence interval −7.21; −2.41]). Conclusion The study adds to the limited evidence on MCA‐PSV in TGA fetuses, supporting a trend of increasing MCA‐PSV MoM with gestational age, although not significant after accounting for multiple measurements. Higher MCA‐PSV MoM correlated with lower neonatal hemoglobin. However, findings do not show that TGA fetuses have elevated MCA‐PSV due to anemia or that VSD influences MCA‐PSV levels.