Paediatrics: Large for gestational age

2021-03-09 12:00 AM

Defined as birth weight >90th centile for gestational age.

Large for gestational age

Defined as birth weight >90th centile for gestational age.

Causes

  • Most frequently constitutional, i.e. large parents.
  • Infant of a mother with diabetes mellitus.
  • Foetal hyperinsulinism, pancreatic islet cell hyperplasia.
  • Hydrops foetalis.
  • Beckwith–Wiedemann syndrome.

Complication

  • Perinatal asphyxia, nerve palsies, shoulder dystocia, fractures.
  • Hypoglycaemia, especially if due to maternal diabetes or in BWS.
  • Problems associated with the underlying cause of LGA.

Management

  • Careful obstetric management to prevent obstetric complications.
  • Examine for associated features, e.g. BWS or signs of birth injury.
  • Prevent hypoglycaemia.

Prognosis 

Generally excellent (unless hydrops foetalis) if managed well.

Infant of a mother with diabetes mellitus

Pathophysiology

Maternal hyperglycaemia l ‘rise’ foetal glucose l I foetal insulin secretion (antenatally has growth hormone function) l macrosomia, organomegaly, and polycythaemia. Rarely, the maternal vascular disease results in foetal IUGR.

Associated complications

  • 2–4 risk of congenital abnormalities: caudal regression syndrome (sacral and femoral agenesis or hypoplasia); transient hypertrophic cardiomyopathy; small left colon syndrome; neural tube defects.
  • Obstetric complications (see Complications): increased risk of spontaneous miscarriage, intrauterine foetal death, and prematurity.
  • Hypoglycaemia: generally resolves as serum insulin level falls.
  • Respiratory disease: respiratory distress.
  • Polycythaemia. Risk of secondary thrombosis (e.g. renal vein).
  • Exaggerated physiological jaundice.
  • Hypocalcaemia and hypomagnesaemia.

Management

Optimize maternal glycaemic control during pregnancy.

Prognosis

  • Normoglycaemia occurs within 48hr in the vast majority.
  • 7 x increased risk of diabetes mellitus in later life.
  • Increased risk of later obesity and, possibly, poor development.