What is the cause of short stature in a 9-month-old child with a height below the 3rd centile (third percentile) and premature birth at 35 weeks gestation?

From the Guidelines

For a 9-month-old child with head circumference at the 3rd centile who was born prematurely at 35 weeks, the GP should refer to pediatrics for further evaluation. The child's premature birth and small head circumference are significant factors that require specialized assessment to rule out underlying neurological issues, genetic conditions, or nutritional deficiencies. Initial investigations should include:

• Complete blood count
• Electrolytes
• Liver and renal function tests
• Thyroid function tests
• Serum calcium, phosphate, and alkaline phosphatase levels
• Ferritin, vitamin D, and zinc levels to assess nutritional status
• Growth hormone and IGF-1 levels may be considered if growth failure is significant 1. A detailed history including feeding patterns, developmental milestones, and family growth patterns is essential. Physical examination should focus on dysmorphic features, neurological status, and other growth parameters (weight and length). The premature birth history is significant as it affects growth trajectory interpretation, and catch-up growth should be monitored using premature-adjusted growth charts. Early intervention is crucial as the first two years represent a critical period for brain development, and addressing any underlying causes promptly can improve outcomes. The evaluation of short stature should consider genetic potential for growth, rate of growth, and pattern of growth, as well as the possibility of pathologic diagnoses such as constitutional delay of growth, familial short stature, or genetic disorders 1. A diagnostic approach to pathologic short stature should differentiate between isolated short stature and short stature associated with other physical and/or developmental abnormalities, and between proportionate and disproportionate short stature 1.

From the Research

Investigation and Blood Tests

• For a 9-month-old child with a head circumference (HC) below the 3rd percentile and premature birth at 35 weeks, investigations should focus on identifying potential cerebral pathologies and assessing kidney function 2, 3.
• Blood tests may include complete blood count (CBC) parameters, such as hemoglobin, hematocrit, erythrocyte, mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) to predict the risk of retinopathy of prematurity (ROP) 4.
• Other blood tests, such as creatinine, cystatin C, and beta-trace protein (BTP), may be used to estimate glomerular filtration rate (GFR) and assess kidney function 3, 5.

Referral to Pediatrician

• Given the potential risks associated with prematurity and low birth weight, referral to a pediatrician is recommended for further evaluation and management 3, 5, 6.
• The pediatrician can assess the child's overall health, monitor kidney function, and provide guidance on screening and management for potential long-term complications, such as chronic kidney disease (CKD) 5, 6.

Potential Long-term Complications

• Premature birth has been linked to an increased risk of kidney dysfunction, high blood pressure, and CKD in childhood and early adulthood 5, 6.
• The child's kidney function should be monitored long-term, with assessments of GFR, total kidney volume (TKV), and cardiovascular risks, including hypertension and vascular stiffness 3, 5.