Short Stature: When Is a Child Too Short?

What counts as short stature

Doctors plot height on standard growth charts. Short stature is defined as height below the 3rd percentile, which means shorter than 97 of 100 children of the same age and sex. Some guidelines use the 2.3rd percentile (2 standard deviations below the mean).

Being short is not itself a disease. What matters most is:

• growth velocity: how fast the child is growing each year
• trajectory: whether they follow their percentile line or fall away from it
• target height: the expected adult height based on the parents' heights

Calculating mid-parental (target) height

• For boys: (father's height + mother's height + 13 cm) ÷ 2
• For girls: (father's height + mother's height − 13 cm) ÷ 2

(Using inches, add or subtract 5 inches instead of 13 cm.) Most children end up within about 8.5 cm (3.5 inches) of this figure.

Normal variants: the most common causes

Both are healthy patterns and need no treatment. Teens with constitutional delay may struggle emotionally while peers grow, and a short course of sex hormones is sometimes offered to start puberty.

Medical causes of short stature

Hormonal causes

• Growth hormone deficiency: slow growth, a young-looking face, increased fat around the middle. Can be present from birth or acquired from pituitary tumors, brain injury or radiation.
• Hypothyroidism: slow growth with tiredness, constipation, weight gain and delayed bone age.
• Cushing syndrome or long-term steroid medicines: weight gain with poor height gain.
• Early puberty: a fast early spurt, then early growth plate closure and short adult height.

Genetic conditions

• Turner syndrome: affects girls; short stature, delayed puberty, sometimes a webbed neck or heart and kidney differences. Any girl with unexplained short stature should be checked for it.
• Noonan syndrome: short stature, heart defects, distinctive facial features.
• Skeletal dysplasias such as achondroplasia: disproportionately short limbs.
• SHOX gene deficiency, Prader-Willi syndrome, Down syndrome, Russell-Silver syndrome.

Chronic illness and nutrition

• Celiac disease: may cause poor growth even without gut symptoms.
• Inflammatory bowel disease, especially Crohn's disease.
• chronic kidney disease, heart disease, lung disease (such as cystic fibrosis) and poorly controlled asthma
• inadequate calorie intake, eating disorders, or failure to thrive
• severe emotional deprivation (psychosocial short stature)

Born small

About 10% of babies born small for gestational age do not catch up by age 2 to 4. Some may benefit from growth hormone.

Idiopathic short stature

Some children are short with no identifiable cause after full assessment. Growth hormone treatment is an option in selected cases.

Clues that suggest a medical cause

• growth rate slowing and height falling across percentiles
• weight falling more than height (suggests nutrition or gut problems)
• weight rising while height slows (suggests hormonal causes)
• disproportion between trunk and limbs
• unusual facial features or other birth differences
• symptoms of chronic illness

How short stature is evaluated

1. Accurate measurements over at least 6 to 12 months to calculate growth velocity.
2. History: birth weight, illnesses, diet, medicines, development, family heights and puberty timing.
3. Examination: body proportions, puberty stage, physical features.
4. Bone age x-ray: an x-ray of the left hand and wrist shows skeletal maturity and remaining growth potential.
5. Blood and urine tests: blood count, kidney and liver function, thyroid tests, celiac antibodies, inflammatory markers, IGF-1 (a marker of growth hormone activity), and a karyotype in girls for Turner syndrome.
6. Specialist tests: growth hormone stimulation tests and pituitary MRI if deficiency is suspected; genetic tests for suspected syndromes.

Treatment

• Normal variants: reassurance and monitoring. No treatment changes adult height meaningfully in familial short stature.
• Treat the underlying cause: thyroid hormone for hypothyroidism, a gluten-free diet for celiac disease, better control of chronic disease, improved nutrition. Catch-up growth often follows.
• Growth hormone therapy: daily or weekly injections for growth hormone deficiency, Turner syndrome, Noonan syndrome, Prader-Willi syndrome, SHOX deficiency, chronic kidney disease, children born small who do not catch up, and selected idiopathic short stature. It works best when started early, before growth plates close.
• Puberty induction: short-term hormones for some teens with significant delay.

Supplements, special diets and stretching exercises marketed to increase height do not work in healthy children.

Frequently asked questions

What is considered short stature?

Short stature is height below the 3rd percentile for age and sex, or more than 2 standard deviations below the average. Most children in this range are healthy. Doctors focus on growth rate and whether height matches what is expected from the parents.

What is the most common cause of short stature?

The two most common causes are familial short stature, where short parents have a short child, and constitutional delay of growth and puberty, where a child grows and matures later than peers. Both are normal variants that need no treatment.

When should I worry about my child's height?

See a doctor if your child is falling across percentile lines on the growth chart, growing less than about 5 cm (2 inches) a year in childhood, is much shorter than expected from family heights, or has other symptoms such as tiredness, diarrhea or delayed puberty.

Can growth hormone make my child taller?

Growth hormone increases adult height in children with growth hormone deficiency and certain other conditions, such as Turner syndrome. It is less effective for idiopathic short stature, where average gains are modest. It does not help once growth plates have closed.

Will a late bloomer catch up in height?

Usually yes. Children with constitutional delay of growth and puberty start puberty later, have their growth spurt later and keep growing for longer. Most reach a normal adult height within their family's range. A bone age x-ray helps predict this.