C-Pep

This study investigated the relationship between early-pregnancy serum C-peptide levels and the risk of gestational diabetes mellitus (GDM) in a nested case-control study involving 332 GDM cases and 664 matched controls. Results showed that women in the highest quartile of C-peptide had a 2.28-fold higher risk of GDM compared to those in the lowest quartile, even after adjusting for confounding factors (P for trend < 0.001). C-peptide was positively correlated with multiple metabolic biomarkers, including fasting insulin, HOMA-IR, fasting glucose, and triglycerides, and negatively correlated with HDL cholesterol and adiponectin. While adding C-peptide to a predictive model improved its performance slightly (C-statistic: 0.66 vs. 0.63; P = 0.008), further validation is required. These findings suggest that early-pregnancy C-peptide levels are positively associated with GDM risk and could have potential as a predictive biomarker.