Effects of umbilical vein flow on midbrain growth and cortical development in late onset fetal growth restricted fetuses: a prospective cross-sectional study.

Objectives: To investigate midbrain growth, including corpus callusum (CC) and cerebellar vermis (CV) and cortical development in late fetal growth restricted (FGR) subclassified according to the umbilical vein blood flow (UVBF) values.
Methods: This was a prospective study on singleton fetuses late FGR with abnormal placental cerebral ratio (PCR). FGR fetuses were further subdivided into normal (≥fifth centile) and abnormal (<fifth centile) UVBF blood flow corrected for AC (UVBF/AC), neurosonography was performed at 33-34 weeks of gestation to assess CC and CV lengths and the depth of Sylvian fissure (SF), parieto-occipital (POF) and calcarine fissures (CF). Neurosonographic variables were normalized for fetal head circumference size.
Results: The study cohort included 60 late FGR, 31 with normal UVBF/AC and 29 with abnormal UVBF/AC values. The latter group showed significant differences in CC (median (interquartile range (IQR) normal 0.96 (0.73-1.16) vs. abnormal UVBF/AC 0.60 (0.47-0.87); p<0.0001)), CV (normal 1.04 (0.75-1.26) vs. abnormal UVBF (AC 0.76 (0.62-1.18)); p=0.0319), SF (normal 0.83 (0.74-0.93) vs. abnormal UVBF/AC 0.56 (0.46-0.68); p<0.0001), POF (normal 0.80 (0.71-0.90) vs. abnormal UVBF/AC l 0.49 (0.39-0.90); p≤0.0072) and CF (normal 0.83 (0.56-1.01) vs. abnormal UVBF/AC 0.72 (0.53-0.80); p<0.029).
Conclusions: Late onset FGR fetuses with of reduced umbilical vein flow showed shorter CC and CV length and a delayed cortical development when compared to those with normal umbilical vein hemodynamics. These findings support the existence of a link between abnormal brain development and changes in umbilical vein circulation.
(© 2024 Walter de Gruyter GmbH, Berlin/Boston.)