What are the types of growth delay in children, such as familial short stature, constitutional growth delay, and late bloomers, and how are they managed, including the use of growth hormone therapy (GHT)?

Types of Growth Delay in Children

The two most common nonpathologic variants of growth delay are familial short stature (FSS) and constitutional delay of growth and puberty (CDGP), which together account for nearly 50% of children referred for short stature evaluation and require distinctly different counseling approaches. 1

Familial Short Stature (FSS)

Key Distinguishing Features:

• Normal bone age that matches chronological age, which is the critical differentiating factor from constitutional delay 2
• Normal growth velocity throughout childhood, maintaining a consistent percentile on growth charts 2
• Early deceleration in linear growth occurs in the first 2-3 years of life, after which the child tracks along a lower but stable percentile 2, 3
• Predicted adult height is short but appropriate for parental heights, calculated using mid-parental target height formulas 2
• No delayed puberty—pubertal timing is normal 2

Growth Pattern:

• Children with FSS show their most significant decline in height standard deviation scores (SDS) during the first 2 years of life (-0.79 SDS), with minimal further decline between ages 2-5 years (-0.01 SDS) 3
• After age 3, growth velocity remains normal and parallel to standard growth curves 1

Management:

• Reassurance is the primary intervention, as no endocrine treatment is indicated 2
• Expected adult height will match genetic potential based on parental heights 2
• Psychological support for the child and family regarding height expectations is recommended 2
• Continue monitoring growth velocity to ensure it remains normal 2

Constitutional Delay of Growth and Puberty (CDGP)

Key Distinguishing Features:

• Delayed bone age compared to chronological age, which is the hallmark finding 4, 2
• Normal or near-normal growth velocity during childhood after initial deceleration 4
• Deceleration of length/height in the first 3 years of life, similar to FSS 4
• Delayed pubertal development—boys with testicular volume <4 ml at age 14 years, girls with breast stage <B2 at age 13.5 years 1
• Final adult height typically within normal range despite delayed growth trajectory 4, 2
• Strong familial pattern often present, with parents reporting similar delayed development 4

Growth Pattern:

• Like FSS, CDGP shows significant height SDS decline in the first 2 years of life (-0.92 SDS), with minimal decline between ages 2-5 years (-0.11 SDS) 3
• Growth velocity increases with rapidity once puberty begins 5
• The delayed bone age indicates increased remaining growth potential compared to chronological age 4

Management:

• Observation is appropriate for most cases, as these children ultimately reach normal adult height 4, 6
• Psychosocial considerations are the primary indication for treatment, not the growth delay itself 6, 7
• If psychological difficulties are significant, short-term treatment with testosterone (boys) or estrogens (girls) may be considered to induce puberty 6, 5
• Growth hormone therapy does NOT improve final adult height in CDGP, despite increasing short-term growth velocity 6, 7
• Oxandrolone increases growth velocity but similarly does not improve final height 6
• Refer to pediatric endocrinology if puberty has not begun by age 14 in boys or 13.5 years in girls 1

"Late Bloomers" (Synonym for CDGP)

The term "late bloomer" is colloquial terminology that refers to the same entity as constitutional delay of growth and puberty 4, 5. These terms are interchangeable in clinical practice.

Failure to Thrive (FTT)

FTT represents a distinctly different category and is not a variant of normal growth:

• FTT indicates pathologic growth failure requiring investigation for underlying disease 1
• Defined by crossing downward through multiple percentile lines, not simply being at a low percentile 8
• Common causes include occult pulmonary, renal, or gastrointestinal disease, endocrinopathies, malnutrition, and genetic disorders 1
• Requires comprehensive evaluation including nutritional assessment, metabolic screening, and consideration of chronic diseases 1

Critical Differentiation from Pathologic Short Stature

Growth velocity is the single most important indicator for distinguishing normal variants from pathologic causes 1, 4:

• Pathologic growth shows continuous decline in height SDS throughout childhood 3
• Children with idiopathic growth hormone deficiency demonstrate persistent height SDS decline in both the first 2 years (-0.78 SDS) AND between ages 2-5 years (-0.77 SDS), unlike FSS and CDGP 3
• Crossing several percentile lines between age 3 years and early adolescence suggests pathologic diagnosis 1

Assessment requires:

• Serial measurements over 4-6 months to calculate growth velocity 1, 4
• Bone age radiography of the left wrist 4, 2
• Mid-parental target height calculation to assess genetic potential 2
• Short stature is formally defined as height <3rd percentile or <-1.88 standard deviations 1

Common Pitfalls to Avoid

• Do not confuse low percentile with abnormal growth—a child growing consistently at the 25th percentile since birth is healthy 8
• Do not use growth hormone for CDGP to improve final height, as it is ineffective for this purpose 6, 7
• Do not delay evaluation if growth velocity is declining—persistent reduced growth velocity beyond 3 months in infants or 6 months in children warrants investigation 1
• Do not assume FSS based on short stature alone—bone age must be normal to exclude CDGP 2
• Some children with CDGP show transient diminished GH secretion that normalizes during puberty, which should not be confused with true GH deficiency 6, 9