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Small for gestational age: Endocrine implications in childhood
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Received: ,
Accepted: ,
How to cite this article: Arora R. Small for gestational age: Endocrine implications in childhood. J Pediatr Endocrinol Diabetes. doi: 10.25259/JPED_IC_77_2026
Abstract
Small for gestational age (SGA) is associated with important endocrine and metabolic consequences extending into adulthood. Although 85–90% of affected children born SGA achieve spontaneous catch-up growth by 2 years of age, 10–15% remain persistently short and may require further evaluation. Children born SGA are also at increased risk of premature adrenarche, early puberty, insulin resistance, type 2 diabetes, and cardiovascular disease, particularly following rapid postnatal weight gain. Regular monitoring of growth, pubertal development, and metabolic health, timely referral to a pediatric endocrinologist, and appropriate growth hormone therapy for persistent short stature are essential to optimize long-term growth and health outcomes.
Keywords
Catch-up growth
Growth hormone therapy
Short stature
Small for gestational age
INTRODUCTION
Small for gestational age (SGA) is defined as birth weight and/or length below−2 standard deviation score (SDS) for gestational age and sex using appropriate reference standards. It affects approximately 10–20% of live births in low- and middle-income countries, including India.[1] SGA must be distinguished from prematurity and intrauterine growth restriction (IUGR). Although, the terms IUGR and SGA are often used as synonyms, they are not interchangeable. IUGR implies a pathological intrauterine process, whereas SGA is a statistical definition. IUGR refers to poor or inadequate gain in estimated fetal weight and abdominal circumference during antenatal period based on two ultrasound measurements, irrespective of the size at birth.[2]
The etiology is multifactorial and includes maternal undernutrition, placental insufficiency, obstetric complications, maternal illness, intrauterine infections, and fetal genetic factors.[1,2] Although most SGA infants demonstrate spontaneous postnatal catch-up growth, a subset remains short and is at increased risk of pubertal disturbances and long-term metabolic complications. The developmental origins of health and disease hypothesis explains how adverse intrauterine environments program long-term metabolic risk, including type 2 diabetes, hypertension, and cardiovascular disease in adulthood.[3]
ENDOCRINE ISSUES IN CHILDREN BORN SGA
Growth
Approximately 85–90% of SGA infants demonstrate spontaneous catch-up growth into the normal height range (>−2 SDS), usually within the first 2 years of life.[1] Catchup growth is most rapid during the first 6 months and may extend up to 4 years in preterm SGA infants.[4].However, 10– 15% fail to achieve adequate catch-up growth and remain short, representing a significant proportion of children with idiopathic short stature.[1,3] Catch-up growth in countries with poor nutrition and relatively low protein dietary content may be delayed up to 4–5 years of age. Birth length is a stronger predictor of persistent short stature than birth weight; children with birth length <−2 SDS have a higher risk of remaining short.[5]
Puberty
Pubertal development is generally normal in children born SGA, although onset may be slightly earlier with faster progression.[6] This may adversely affect final adult height. Girls born SGA, particularly those with rapid postnatal weight gain, are at increased risk of premature adrenarche, early menarche, and polyendocrine metabolic ovarian syndrome (PMOS).[7]
Thyroid
Preterm SGA infants may have higher thyrotropin levels within the normal range and an increased risk of transient thyroid dysfunction.[8]
Bone health
Bone mineral density is on average lower but generally within the normal range.[9]
Insulin resistance
Insulin resistance may develop early in life in children born SGA, particularly in those with rapid postnatal weight gain. The insulin resistance is sharply amplified by accelerated fat mass accumulation and obesity in those with rapid weight gain in the first 3 months of life, and in those with a high body mass index (BMI).[10] This risk is further amplified by obesity and genetic predisposition. Long-term consequences include type 2 diabetes, dyslipidemia, and cardiovascular disease.[11]
ASSESSMENT
A detailed evaluation should include birth history (weight, length, and gestation), maternal risk factors, and assessment for dysmorphism, asymmetry, and developmental delay. Early growth monitoring with Intergrowth 21 charts[12] provides useful information regarding the growth pattern of neonates born SGA. The weight and length should be monitored every 3 months during the first year of life, 6-monthly in the second year of life, and yearly thereafter until the child reaches their genetic height potential or a height in the normal range.
Warning/red flag signs
Length below −2.5 SDS beyond 2–3 years
Growth velocity that is less than the expected rate of height gain for a child’s age and sex over a specific time period, usually falling below the 25th percentile (or <−2 standard deviation) on standard growth velocity charts
Downward crossing of centiles on growth chart
Disproportionate short stature
Early or rapidly progressive puberty
Excessive weight gain relative to height—monitored by weight for length or BMI.
Investigations
First-line investigations include complete blood count, erythrocyte sedimentation rate, renal and liver function tests, thyroid function tests, celiac screening, and insulin-like growth factor-1 (IGF-1).[3] Insulin-like growth factor-binding protein-3 (IGFBP3) may improve diagnostic yield. Further evaluation includes bone age assessment, growth hormone (GH) stimulation testing (if indicated), and genetic testing in the presence of dysmorphic or syndromic features.[1,3]
MANAGEMENT
Nutrition and growth optimization
Balanced catch-up growth should be encouraged, with avoidance of excessive caloric intake leading to disproportionate weight gain. Exclusive breastfeeding followed by appropriate complementary feeding with adequate protein and micronutrients is recommended.[7]
Growth hormone therapy
GH therapy is recommended in children born SGA with persistent short stature after the age when spontaneous catch-up growth is unlikely (2–4 years depending on guidelines).[1] The recommended dose is 0.033–0.067 mg/kg/day. Early initiation is associated with better adult height outcomes.[1,3].Monitoring includes growth velocity (primary parameter), IGF-1 levels (3–6 months, then annually), thyroid function, glucose, and metabolic parameters in high-risk children. A first-year height gain of >0.5 SDS indicates good response. Therapy is discontinued when growth velocity falls below 1 cm over 6 months or epiphyseal closure occurs.[1]
Pubertal considerations
Annual pubertal assessment should begin at 8 years in girls and 9 years in boys. Rapid progression, significant bone age advancement, or early menarche warrants referral to a pediatric endocrinologist. Gonadotropin-releasing hormone (GnRH) analogs may be considered in selected children with early or rapidly progressive puberty and compromised predicted adult height.[1]
Metabolic and cardiovascular risk
Excessive weight gain (a change in weight for length >+0.67 SDS, that is, passing weight SDS lines in upward direction), particularly during early life, should be avoided.[7] Routine metabolic screening is not required in all children. Screening is recommended in overweight or obese children, especially after 8–10 years of age.[13] Lifestyle modification with emphasis on diet and physical activity remains the cornerstone of prevention.
Referral guidance
Referral to a pediatric endocrinologist is recommended in the following situations. Timely referral optimizes growth and pubertal outcomes.
No catch-up growth by 2–4 years
Height <−2.5 SDS
Poor growth velocity
Suspected syndromic diagnosis
Early or rapidly progressive puberty
Consideration for GH therapy
Presence of metabolic complications.
CONCLUSION
Children born SGA require structured longitudinal follow-up focusing on growth, pubertal development, and metabolic health. While most achieve spontaneous catch-up growth, a subset requires early identification and intervention. GH therapy, when indicated, significantly improves adult height outcomes. Balanced nutrition and prevention of excessive weight gain are essential to reduce long-term metabolic risk. Early recognition and timely referral remain key to optimizing outcomes.
Ethical approval:
The Institutional Review Board approval is not required.
Declaration of patient consent:
Patient’s consent was not required as there are no patients in this study.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Financial support and sponsorship: Nil.
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