Actual incidence of severe neonatal hypoglycemia in non-risk term neonates: A 10 year survey of all cases in Toyama Prefecture, Japan

Background: Severe neonatal hypoglycemia may cause irreversible neurological sequelae. Although blood glucose (BG) screening in term neonates without risk factors for hypoglycemia (non-risk neonates) is not recommended in the current guidelines, severe hypoglycemia can occur in such neonates. To evaluate the necessity of BG screening in non-risk neonates, it is important to determine the accurate incidence of severe hypoglycemia in those neonates. Methods: We conducted a 10 year survey of all normal-weight term neonates diagnosed with severe neonatal hypoglycemia who were treated at secondary- and tertiary-level neonatal centers in Toyama Prefecture, Japan, between January 2011 and December 2020. Results: During the study period, 11 cases of severe neonatal hypoglycemia (six of which occurred in non-risk neonates) were identified. The overall incidence of severe hypoglycemia was 1 in 5,827 normal-weight term births, and the incidence in non-risk neonates was 1 in 10 682 normal-weight term births. All of the cases in non-risk neonates were diagnosed as hyperinsulinemic hypoglycemia. Conclusions: This is the first population-based study to have identified the actual incidence of severe pathological neonatal hypoglycemia in non-risk neonates. The incidence was not low compared with those of the newborn screening disorders, justifying the necessity of BG screening even in non-risk neonates.