Lack of Growth in Children: Causes and When to Worry

What counts as poor growth

Doctors judge growth with a growth chart, plotting height, weight and (in babies) head size over time. Two things matter more than any single measurement:

• Where the child sits: below the 3rd percentile (shorter than 97 of 100 children of the same age and sex) is considered short stature.
• Growth velocity: how fast the child is growing. A child steadily following a low percentile is usually healthy. A child whose growth is falling across percentile lines needs evaluation, even if they are still in the normal range.

Typical growth rates:

Failure to thrive describes poor weight gain, usually in babies and toddlers. Poor weight gain usually comes first, with height slowing later. When height slows first and weight is normal or high, a hormone cause is more likely.

Normal variants (most common)

Familial short stature

Children of short parents are often short too. They are born at a normal size, then settle on a low percentile and grow at a normal rate, with puberty at the usual time. Their final height matches their parents'.

Constitutional delay of growth and puberty

These "late bloomers" grow at a normal rate but are short during childhood, with a delayed bone age and late puberty. They have a late growth spurt and catch up to a normal adult height. A parent often had the same pattern.

Medical causes of lack of growth

Nutrition

Not getting enough calories is the most common cause of failure to thrive worldwide. Reasons include feeding difficulties, restrictive diets, food insecurity, and eating disorders in older children. See malnutrition.

Gut conditions

• Celiac disease: a reaction to gluten that damages the gut lining. Poor growth can be the only sign. Bloating, diarrhea, constipation and anemia are common.
• Crohn's disease: growth slowing can appear before gut symptoms in children.
• Cystic fibrosis and other causes of poor absorption.

Hormone problems

• Hypothyroidism: slowing growth, weight gain, tiredness, constipation and delayed puberty.
• Growth hormone deficiency: slow growth with a chubby build and a young-looking face. It can be present from birth or caused by brain tumors, surgery or radiation.
• Cushing syndrome: from long-term high-dose steroid medicines or, rarely, tumors. Weight goes up while height slows.
• Poorly controlled type 1 diabetes.

Genetic conditions

• Turner syndrome: affects girls, causing short stature and absent or delayed puberty. It may be the only obvious sign, so all girls with unexplained short stature should be tested.
• Noonan syndrome, Down syndrome, Prader-Willi syndrome and skeletal dysplasias such as achondroplasia, which cause short limbs.

Chronic illness

Kidney disease, heart disease, severe asthma treated with high-dose steroids, and other long-term conditions can slow growth.

Born small

Babies born small for gestational age who have not caught up by age 2 to 4 may stay short and can qualify for growth hormone treatment.

Psychosocial causes

Severe emotional neglect or stress can suppress growth hormone and slow growth. Growth often recovers when the environment improves.

How doctors evaluate a child who is not growing

1. Accurate measurements plotted over at least 6 to 12 months to calculate growth velocity.
2. Mid-parental height: an estimate of the child's genetic target from the parents' heights.
3. History: birth size, feeding, diet, bowel habits, chronic illness, medicines (including steroid inhalers), development and family growth patterns.
4. Examination: body proportions, puberty stage, signs of genetic syndromes, thyroid size.
5. Bone age X-ray of the left hand: a delayed bone age suggests more growth time ahead, as in constitutional delay or hormone problems.
6. Blood tests: blood count, kidney and liver function, celiac antibodies, thyroid function, inflammatory markers, and IGF-1 (a marker of growth hormone).
7. Chromosome test (karyotype) for girls, to check for Turner syndrome.
8. Growth hormone stimulation tests and a brain MRI if growth hormone deficiency is suspected.

Treatment

Treatment depends on the cause:

• Normal variants: reassurance and monitoring. Some boys with very delayed puberty are offered a short course of testosterone to start puberty.
• Nutrition: dietitian support, high-energy feeds, and help with feeding difficulties.
• Celiac disease: a strict gluten-free diet. Catch-up growth usually follows.
• Hypothyroidism: thyroid hormone tablets.
• Growth hormone deficiency, Turner syndrome and some other conditions: daily or weekly growth hormone injections, ideally started early.
• Chronic illness: better control of the underlying disease.

Frequently asked questions

When should I worry that my child is not growing?

See a doctor if your child's height or weight has dropped across two major percentile lines, they grow less than about 2 inches (5 cm) a year after age 3, they are much shorter than expected from family heights, or they have other symptoms such as tummy problems or tiredness.

What is the most common cause of short stature?

The most common causes are normal variants: familial short stature (short parents) and constitutional delay (late bloomers). These children are healthy and grow at a normal rate. Medical causes are less common but important to rule out.

Can a child catch up on growth?

Yes, often. Late bloomers catch up during a later puberty. Children with celiac disease, hypothyroidism or poor nutrition usually show catch-up growth once treated. The earlier the cause is found, the better the chance of reaching full potential height.

What is the difference between failure to thrive and short stature?

Failure to thrive usually refers to poor weight gain, mainly in babies and toddlers, often linked to nutrition or illness. Short stature refers to height below the 3rd percentile, which is often normal but can reflect hormone or genetic conditions.

Does growth hormone help short children?

Growth hormone helps children with proven growth hormone deficiency, Turner syndrome, chronic kidney disease, Prader-Willi syndrome and some children born small. It is not used for healthy short children from short families, where benefit is small.