Insulin and glucagon levels of umbilical cord blood in appropriate for gestational age - preterm infants with or without postnatal hypoglycemia

PURPOSE To determine whether serum insulin and glucagon levels of umbilical cord blood correlate with subsequent postnatal hypoglycemia in appropriate for gestational age (AGA) - preterm infants at different gestational ages (GAs). METHODS The serum insulin and glucagon levels of umbilical cord blood were measured using magnetic bead based multiplex immunoassay in 69 AGA - premature infants, stratified according to GA: GA 23-30 weeks, early preterm (EP, n=31); GA 31-34 weeks, late preterm (LP, n=38). Postnatal hypoglycemia was defined as a capillary glucose level <40 mg/dL within the first 60 minutes of life, regardless of GA. RESULTS The capillary glucose concentration in EP infants (65.5±21.2 mg/dL) was significantly higher than that of LP infants (55.9±17.3 mg/dL) (P=0.043). The serum glucagon level in EP infants (44.3±28.7 pg/mL) was significantly higher than that in LP infants (28.1±13.6 pg/mL) (P=0.006). There was not a significant difference in serum insulin level between EP and LP infants (372.7±254.2 pg/mL vs. 372.4±209.1 pg/mL, P=0.996). There was a significant difference in the serum glucagon level between infants with and without hypoglycemia (27.7±8.9 mg/dL vs. 36.8±24.6 mg/dL, P=0.036), but not in the serum insulin level (451.9±256.9 pg/mL vs. 357.4±222.2 pg/mL, P=0.211). Postnatal glucose concentration within the first 60 minutes of life had a significant positive correlation with serum glucagon levels (r=0.256, P=0.034), but not with serum insulin levels (r=-0.020, P=0.867). CONCLUSION Lower glucagon levels of cord blood were seen in premature infants with higher GA, which might contribute to the occurrence of postnatal hypoglycemia.