Paediatrics: Large 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.

Complications

·  Perinatal asphyxia, nerve palsies, shoulder dystocia, fractures.

·  Hypoglycaemia, especially if due to maternal diabetes or in BWS.

·  Problems associated with the underlying cause 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, organomega-ly, and polycythaemia. Rarely, maternal vascular disease results in foetal IUGR.

Associated complications

·  2–4 x 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 b 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 vast majority.

·  7 x increased risk of diabetes mellitus in later life.

·  Increased risk of later obesity and, possibly, poor development.