Diabetic fetopathy and neonatal hypoglycaemia

Definition

• Diabetic fetopathy denotes the changes in infants of diabetic mothers, the term diabetic mother covering both pre-existing type 1 or type 2 diabetes and gestational diabetes.
• Neonatal hypoglycaemia is the most common metabolic disturbance of the newborn period; the glucose level at which brain damage occurs is unknown.

Occurrence & epidemiology

Epidemiology

• Hypoglycaemia occurs in 5–27% of infants of diabetic mothers; further risk groups are preterm infants and infants small or large for gestational age.

Aetiopathogenesis

Aetiology and pathogenesis

• Increased fetal insulin secretion leads to hypertrophy and hyperplasia of the β cells and to growth of insulin-dependent organs such as liver, kidneys, skeletal muscle and heart (organomegaly).
• After cord clamping the glucose supply ends while insulin levels remain high; blood glucose reaches its lowest point between the first and third hour of life.
• Insulin antagonises cortisol, which stimulates surfactant synthesis; this results in an increased risk of respiratory distress syndrome.

Clinical features

Main problem: Postnatal hypoglycaemia

• The main problem for the newborn is postnatal hypoglycaemia, as fetal hyperinsulinism with absent glucose supply.

Other transitional problems and findings

• Respiratory distress syndrome can be caused by reduced surfactant formation.
• A typically reversible myocardial hypertrophy due to glycogen deposition is a typical cardiac finding.
• Other findings include polycythaemia with an elevated haematocrit and consecutive hyperbilirubinemia, as well as hypocalcaemia and hypomagnesaemia.

Clinical features and complications

• Macrosomic infants (birthweight above the 90th centile) have a chest circumference exceeding head circumference and organomegaly; they more often suffer brachial plexus injury, clavicular fracture and asphyxia.
• Hypoglycaemic newborns usually show tremors and hyperalertness, but also hypotonia, lethargy and weak sucking; however, hypoglycaemia is mostly asymptomatic and may persist for up to 72 hours.

Keep learning in the app

Further reading (selection)

1. Pediatr Endocrinol Diabetes Metab 2024: Infant of a diabetic mother: clinical presentation, diagnosis (Übersichtsarbeit; Titel gekürzt) (PubMed Central)
2. StatPearls: Neonatal Hypoglycemia (NCBI Bookshelf)
3. DocCheck Flexikon, Neonatale Hypoglykämie

Cross-references