Glucagon and insulin cord blood levels in very preterm, late preterm and full-term infants

BACKGROUND: The cause of hyperglycemia, a frequent disorder of glucose homeostasis in very preterm infants, is still unknown. OBJECTIVES: Determine the glucagon and insulin plasma levels at birth in healthy, appropriate for gestational age (AGA) infants born by elective cesarean section (ECS), at different gestational age. METHODS: Glucagon, insulin and the homeostasis model of assessment-insulin resistance (HOMA-IR) index were measured in cord blood in 52 AGA infants divided into three groups: ≤30 weeks, very preterm (VP, n=16); 35-37 weeks, late preterm (LP, n=18); ≥38 weeks, full term (FT, n=18). RESULTS: In all enrolled infants, Apgar score at 5 min after birth was 7 to 9. In VP infants, glucagon levels were higher than those in LP (533±116 vs. 211±28 pg/mL) (p<0.001) and FT infants (533±116 vs. 226±20 pg/mL) (p<0.001). Insulin levels were higher in VP than in LP (8.61±2.48 vs. 3.98±0.94 mU/L) (p<0.001) and FT infants (8.61±2.48 vs. 4.56±1.2 mU/L) (p<0.001). HOMA-IR index was higher in VP than in LP and FT infants (30.6±10.2 vs. 11.9±3.04 and 13.5±1.6, respectively) (p<0.001). CONCLUSION: We concluded that very low gestational age is associated with high glucagon plasma levels and insulin-resistance, which could explain hyperglycemia in the very preterm infants.