Glycemic variability in preterm infants receiving intermittent gastric tube feeding: report of three cases

Late-onset hypoglycemia (day 12-16, blood glucose <50 mg/dL) was detected in three preterm infants (birthweight 998-1780 g; gestational age 27-30 weeks) by routine screening. All infants showed high serum insulin levels and extremely low ketone levels at the time of hypoglycemia. Continuous glucose monitoring was conducted at 31-34 weeks' postconceptual age when the infants were receiving intermittent gastric tube feeding with no intravenous glucose infusion. The continuous glucose monitoring results showed characteristic postprandial glucose increases and subsequent sharp deceases along with many hyper- and hypoglycemic events. This fluctuating pattern disappeared at 38-40 weeks' postconceptual age. These observations suggest that prolonged insulin oversecretion may be associated with early aggressive intravenous nutrition, and that large glycemic variability is a common feature of tube-fed preterm infants that can be explained by immature glucose homeostasis.