Delayed Bone Age in Children: Causes, Diagnosis, and What It Means for Growth
Medically Reviewed by Dr Devin Stone ND Updated: 05/30/2026
Has your child been told they have a delayed bone age? If so, you may be wondering whether they will eventually catch up in height, if they are a "late bloomer," or whether an underlying growth disorder could be affecting their development.
A delayed bone age is one of the most important findings in pediatric growth evaluation because it helps predict future growth potential and can provide valuable insight into why a child may be shorter than expected.
At HGHforChildren.com, delayed bone age is one of the most common reasons families seek a pediatric growth consultation. Understanding what bone age means—and what it doesn't mean—is essential for making informed decisions about your child's growth and development.
What Is Bone Age?
Bone age is a measure of skeletal maturity rather than chronological age.
While your child's chronological age is simply their age in years, bone age evaluates how mature their bones are compared to typical children of the same age.
Bone age is typically determined using an X-ray of the left hand and wrist and comparing the image to standardized pediatric growth references.
For example:
- Chronological Age: 12 years
- Bone Age: 10 years
This means the child's skeletal development is approximately two years behind average.
In many cases, a delayed bone age indicates that growth plates may remain open longer, potentially allowing for additional future growth.
Why Is Bone Age Important?
Bone age is one of the most valuable tools available when evaluating:
- Short stature
- Poor growth velocity
- Delayed puberty
- Constitutional growth delay
- Growth hormone deficiency
- Predicted adult height
- Growth plate maturity
Without bone age testing, it is often difficult to accurately estimate how much growth potential remains.
A child who is short today may still have significant growth ahead if their skeletal development is delayed.
What Causes Delayed Bone Age?
Several factors can contribute to delayed skeletal maturation.
Constitutional Growth Delay
The most common cause of delayed bone age is Constitutional Growth Delay (CDG).
These children are often called "late bloomers."
Typical features include:
- Short stature during childhood
- Delayed puberty
- Delayed bone age
- Family history of late growth
- Normal eventual adult height
Many children with constitutional growth delay experience a later growth spurt and continue growing after their peers have stopped.
Growth Hormone Deficiency
Children with growth hormone deficiency frequently demonstrate delayed skeletal maturation.
Additional findings may include:
- Slow growth velocity
- Low IGF-1 levels
- Delayed puberty
- Falling off growth curves
Because constitutional growth delay and growth hormone deficiency can appear similar, additional testing is often necessary.
Hypothyroidism
Thyroid hormone plays a critical role in childhood growth and skeletal development.
Untreated hypothyroidism may cause:
- Delayed bone age
- Slowed growth
- Fatigue
- Weight gain
- Delayed puberty
This is why thyroid testing is routinely included in pediatric growth evaluations.
Chronic Illness
Medical conditions that can affect growth include:
- Celiac disease
- Inflammatory bowel disease
- Kidney disease
- Chronic inflammatory conditions
- Malnutrition
When growth slows, the body often prioritizes survival over skeletal development.
Delayed Puberty
Sex hormones contribute significantly to bone maturation.
Children with delayed puberty often show delayed bone age because skeletal development progresses more slowly before puberty begins.
How Is Bone Age Measured?
The standard method involves:
Left Hand and Wrist X-Ray
A simple X-ray is taken of the left hand and wrist.
The image is then compared to established growth standards using:
Greulich and Pyle Atlas
The Greulich and Pyle method is the most widely used bone age assessment system in pediatric endocrinology.
A radiologist compares your child's bones to thousands of reference images to determine skeletal age.
What Does a Delayed Bone Age Mean?
A delayed bone age generally suggests that a child's skeletal development is younger than their actual age.
This often means:
- Growth plates may remain open longer
- Puberty may occur later
- Additional growth potential may remain
- Adult height prediction may be higher than current height suggests
For many children, delayed bone age is actually reassuring because it indicates there may still be time to grow.
Delayed Bone Age vs Chronological Age
| Chronological Age | Bone Age | Interpretation |
|---|---|---|
| 10 years | 10 years | Normal skeletal maturity |
| 12 years | 10 years | Delayed bone age |
| 14 years | 11 years | Significant delay |
| 15 years | 13 years | Moderate delay |
| 16 years | 16 years | Skeletal maturity appropriate |
The degree of delay can provide clues about the underlying cause and remaining growth potential.
Can Delayed Bone Age Increase Final Adult Height?
Not necessarily.
A delayed bone age does not automatically mean a child will become taller than expected.
Instead, it means the child may have more time remaining to grow.
Final adult height is still influenced by:
- Genetics
- Growth hormone production
- Nutrition
- Medical conditions
- Puberty timing
- Growth plate health
Bone age is one piece of the overall growth puzzle.
How Much Delayed Bone Age Is Normal?
Small differences between chronological age and bone age are common.
Generally:
- Less than 1 year difference may be normal
- 1–2 years delayed is often seen in constitutional growth delay
- More significant delays warrant further evaluation
The interpretation always depends on the child's overall growth pattern.
Does Delayed Bone Age Mean My Child Is a Late Bloomer?
Sometimes—but not always.
Many children with delayed bone age are simply late bloomers.
However, delayed bone age can also occur with:
- Growth hormone deficiency
- Thyroid disorders
- Nutritional deficiencies
- Chronic illness
- Genetic growth disorders
This is why bone age should never be interpreted in isolation.
Can Bone Age Predict Adult Height?
Bone age is commonly used to estimate predicted adult height.
Physicians combine:
- Current height
- Chronological age
- Bone age
- Growth velocity
- Family height history
to estimate future growth potential.
While predictions are not perfect, bone age remains one of the best tools available for forecasting adult height.
What Tests Are Usually Ordered with a Bone Age?
A complete pediatric growth evaluation may include:
Growth Measurements
- Height percentile
- Weight percentile
- BMI
- Growth velocity
Laboratory Testing
- IGF-1
- IGFBP-3
- Thyroid panel
- CBC
- Comprehensive metabolic panel
- Vitamin D
- Celiac screening
Additional Testing
- Growth hormone stimulation testing
- Pituitary imaging
- Genetic testing when indicated
When Should Parents Seek Evaluation?
A growth assessment may be appropriate if your child:
- Is below the 3rd percentile for height
- Has slowed growth significantly
- Has fallen off their growth curve
- Has delayed puberty
- Appears significantly younger physically than peers
- Has a delayed bone age on imaging
- Has concerns about future adult height
Early evaluation can help determine whether delayed bone age represents a normal growth pattern or a potentially treatable condition.
Frequently Asked Questions
Is delayed bone age bad?
Not necessarily. In many cases, delayed bone age simply means a child has additional time remaining to grow.
Can delayed bone age be corrected?
The goal is not to correct bone age itself but rather identify and address any underlying condition affecting growth.
Is delayed bone age the same as growth hormone deficiency?
No. Growth hormone deficiency is one possible cause of delayed bone age, but many children with delayed bone age have normal growth hormone production.
Can a child with delayed bone age still reach a normal adult height?
Yes. Many children with delayed bone age ultimately reach an adult height within their genetic target range.
How often should bone age be repeated?
Depending on the situation, repeat bone age studies are often performed every 6–12 months to monitor skeletal maturation and growth potential.
Why Families Choose HGHforChildren.com
At HGHforChildren.com, we specialize in comprehensive pediatric growth evaluations for children with:
- Delayed Bone Age
- Constitutional Growth Delay
- Growth Hormone Deficiency
- Idiopathic Short Stature
- Delayed Puberty
- Poor Growth Velocity
- Low IGF-1
- Pituitary Disorders
Our team helps families understand growth potential, identify underlying causes of delayed growth, and determine whether additional testing or treatment may be appropriate.
Medical References
- Pediatric Endocrine Society Clinical Resources on Growth Disorders
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Growth Disorders Information
- MedlinePlus: Growth Disorders in Children
- National Library of Medicine (PubMed) Bone Age Assessment Research
- Greulich and Pyle Atlas Reference Overview (NCBI)
Medically Reviewed By
Dr. Devin Stone, ND
Founder, HGHforChildren.com
Dr. Devin Stone is a naturopathic doctor specializing in pediatric growth assessment, delayed bone age evaluation, hormone optimization, and evidence-based growth support. He works with families nationwide to evaluate short stature, delayed puberty, constitutional growth delay, growth hormone deficiency, low IGF-1, and other pediatric growth concerns. His approach combines growth chart analysis, bone age interpretation, laboratory testing, and individualized treatment planning to help children maximize their growth potential.
Last Medically Reviewed: May 2026
