The relationship between neonatal hypoglycaemia and cord blood C-peptide levels in neonates of birthing individuals with type 1 diabetes

Introduction: Neonates of individuals with type 1 diabetes (T1D) are at increased risk of neonatal hypoglycaemia. It is hypothesised that this is a result of birthing-individual hyperglycaemia and subsequent foetal hyperinsulinemia. Aims: To test for association between clinically significant neonatal hypoglycaemia (requiring intravenous glucose treatment) and cord-blood c-peptide (CBCP) concentrations in birthing-individuals with T1D. Materials and Methods: This is a prospective cohort study of individuals with T1D followed at a single tertiary centre. Clinical variables and glucose control during pregnancy were recorded. Cord-blood was collected and CBCP concentrations determined. The correlation between clinically significant neonatal hypoglycaemia and CBCP concentrations was determined. Results: Fifty-four pregnant individuals and their newborns were included in the study. Individuals to neonates who experienced hypoglycaemia had longer diabetes duration (19 vs. 13 years, respectively, p = 0.023), higher HbA1c at conception (7.3 [6.3–8.8] vs. 6.5 [6.0–7.0], respectively, p = 0.042) and higher rates of caesarian section (73.3% vs. 28.2%, respectively, p = 0.005) than individuals to those who did not. CBCP levels were significantly higher in neonates with clinically significant neonatal hypoglycaemia as compared to those who did not experience hypoglycaemia (3.3 mcg/L vs. 1.9 mcg/L, respectively, p = 0.002). After adjustment for possible confounders, every 1 unit higher in CBCP level was associated with a 1.46 (1.02–2.09, p = 0.035)—fold greater risk for neonatal hypoglycaemia. No significant differences were observed in either birthing individual complications or glucose control indices during pregnancy between the two groups. Conclusions: In neonates of individuals with T1D, higher CBCP levels are an independent risk factor for clinically significant neonatal hypoglycaemia.