Paediatrics: Small for gestational age

Small for gestational age

SGA is birth weight <10th centile for gestational age. Intrauterine growth restriction (IUGR) is failure of growth in-utero that may or may not result in SGA.

·Symmetric (proportional) SGA: all growth parameters symmetrically small; suggests foetus affected from early pregnancy, e.g. chromosomal disorder or constitutional.

·Asymmetric (disproportional) SGA: weight centile < length and head circumference. Usually because of IUGR due to insult in late pregnancy, e.g. pre-eclampsia. Asymmetric SGA infants at risk of complications.

Causes

·Constitutional, i.e. small parents (commonest).

·Restricted foetal O₂ or glucose supply, e.g. placental dysfunction, maternal hypertension, multiple pregnancy, maternal illness.

·Foetal abnormality, e.g. chromosomal disorders, congenital anomalies and syndromes, congenital infection.

·Maternal substance exposure, e.g. alcohol, smoking, therapeutic or other drugs.

Complications

·Incre Risk of foetal death and asphyxia (SGA indicates foetal compromise).

·May have congenital infection, toxoplasmosis, others, rubella, cytomegalovirus, herpes virus II (TORCH) or malformation.

·Hypoglycaemia.

·Hypothermia.

·Polycythaemia.

·Necrotizing enterocolitis and/or intolerance of feeds.

·Thrombocytopenia/neutropenia/coagulopathy.

·Meconium aspiration syndrome.

Management

Ideally manage on a postnatal ward with increased ratio of midwives.

·Routine postnatal care.

·Evaluate clinically for features suggestive of underlying cause.

·Particular attention to thermal care and blood glucose monitoring.

·Observe temperature, pulse, and respiration for at least the first 48hr.

·Admit to neonatal unit if birth weight <1800g.

·Well infants can be discharged when: they are sucking all feeds 3–4-hourly; weight gain is satisfactory (20–30g/day); body temperature is maintained at room temperature; mother is capable of caring for infant.

Prognosis

Neurodevelopmental impairments more common in SGA infants. Symmetric SGA infants often stay small. The Barker hypothe-sis suggests IUGR infants with a small placenta are at risk in later life of coronary disease, stroke, obesity, and hypertension.