Cord Blood Metabolomic Profiling Reveals Fetal Reprogramming in Intrauterine Growth Restriction

Introduction: Intrauterine growth restriction (IUGR) alters fetal metabolic programming, increasing the risk for immediate neonatal complications and long-term health complications. The exact biochemical shifts underlying this are not fully understood. Umbilical cord blood reflects the fetal metabolic environment at birth. To compare IUGR and appropriate-for-gestational-age (AGA)/healthy pregnancies, we employed untargeted metabolomics on umbilical cord blood for identifying metabolic signatures and disrupted metabolic pathways to better understand fetal growth restriction and guide future postnatal interventions.

Methods: Following informed maternal consent, a matched case-control study was conducted comprising 30 IUGR and 30 AGA pregnancies. Fresh umbilical cord blood samples were obtained at delivery, and whole blood samples were analyzed for untargeted metabolomics using gas chromatography-mass spectrometry. The area-under-the-curve values for metabolites obtained after noise reduction and elimination of reaction intermediates were processed in MetaboAnalyst 6.0. Univariate and multivariate analyses, as well as pathway enrichment analysis, were used to identify potential biomarkers and disrupted metabolic pathways.

Results: Univariate and multivariate models revealed a significant metabolic shift, with significant elevations of cholesterol, 2-ketoglutaric acid, L-5-oxoproline, and pyruvic acid and downregulation of 1-monopalmitin in the cases. Receiver Operating Characteristic Curve evaluations established a 5-biomarker panel with a diagnostic area under the curve of 0.946. Enrichment analysis revealed severe disruption of lipid homeostasis, with steroid and cholesterol biosynthesis showing statistical enrichment. Pathway analysis showed that hypercholesterolemia is associated with mitochondrial energy metabolism, severely impairing the TCA cycle and glyoxylate metabolism.

Conclusions: Cord blood metabolomics effectively differentiates IUGR from AGA pregnancies, uncovering significant fetal metabolic reprogramming characterized by dysregulated lipid homeostasis and redirected steroidogenesis, coupled with mitochondrial metabolic impairment. The identified 5-metabolite panel demonstrates exceptional discriminatory power, offering a highly promising, clinically translatable biochemical foundation to complement standard diagnostic tools for identifying pathologically growth-restricted fetuses and for identifying early therapeutic targets to mitigate the long-term metabolic consequences of IUGR.