Neonatal Hypoglycemia By Kevin C Dysart, MD, Nemours / Alfred I duPont Hospital for Children Reviewed / Revised Mar 2021 | Modified Sep 2022 View Patient Education Etiology Symptoms and Signs Diagnosis Treatment Key Points Hypoglycemia is difficult to define in neonates but is generally considered a serum glucose concentration < 40 mg / dL (< 2.2 mmol / L) in symptomatic term neonates, < 45 mg / dL (< 2.5 mmol / L) in asymptomatic term neonates between 24 hours and 48 hours of life, or < 30 mg / dL (< 1.7 mmol / L) in preterm neonates in the first 48 hours.