Growth Delay in Children

What counts as growth delay

Children grow fastest in the first two years. After that, until puberty, most grow a steady 2 to 2.5 inches (5 to 6 cm) a year. Doctors plot height on growth charts, which show percentiles: a child on the 25th percentile is taller than 25 of 100 children of the same age and sex.

Healthy children usually stay near the same percentile line from about age 2 until puberty. Doctors become concerned when a child:

• is below the 3rd percentile for height
• crosses downward through two major percentile lines
• grows less than about 1.5 to 2 inches (4 to 5 cm) a year before puberty
• is much shorter than expected from the parents' heights

A child who is short but growing at a normal rate along their own line is very different from a child whose growth is slowing. The second needs more investigation. See short stature for the symptom-focused view and poor growth for more on growth charts.

Normal variants: the most common causes

Constitutional delay of growth and puberty

These are the "late bloomers". The child is born a normal size, slows down to a lower percentile around 6 months to 3 years, then grows at a normal rate but stays short. Puberty and the growth spurt come 2 or more years later than in classmates. Often a parent was also a late developer. Because bone age (the maturity of the skeleton) lags behind, these children keep growing for longer and usually reach a normal adult height for their family. It is more commonly noticed in boys.

Familial short stature

The child is short because the parents are short. Growth rate is normal, puberty comes on time, and bone age matches actual age. Adult height is short but normal for the family.

Medical causes of growth delay

Hormone problems

• Growth hormone deficiency: slow growth with a chubby, younger-looking appearance. It can be present from birth or acquired after brain tumors, surgery or radiation.
• Hypothyroidism: an underactive thyroid slows growth, often with tiredness, constipation, dry skin and weight gain.
• Excess cortisol: from long-term high-dose steroid medicines or Cushing syndrome. Weight goes up while height stalls.

Chronic illness and nutrition

• Celiac disease: can cause slow growth even without obvious gut symptoms.
• Crohn's disease: slow growth may come before belly pain and diarrhea.
• Chronic kidney disease, poorly controlled asthma, heart disease and cystic fibrosis.
• Not getting enough calories, from restricted diets, feeding problems or food insecurity.

In these conditions weight usually falls off before height, while hormone problems tend to slow height more than weight.

Genetic and birth-related causes

• Turner syndrome: a chromosome condition in girls. Short stature may be the only early sign, which is why every short girl without an obvious cause should have a chromosome test.
• Noonan syndrome, SHOX gene deficiency and Down syndrome.
• Skeletal dysplasias such as achondroplasia, with short limbs or unusual body proportions.
• Being born small for gestational age: most catch up by age 2, but about 1 in 10 do not.

Emotional deprivation

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

Growth delay in infants (faltering growth)

In babies, slow weight gain usually comes before slow height gain. Common reasons are feeding difficulties, reflux, milk allergy and not enough intake. Less often there is a heart, gut, kidney or genetic problem. See failure to thrive.

How doctors evaluate growth delay

1. Accurate measurements: height measured on a wall-mounted stadiometer, plotted with past measurements to calculate growth rate.
2. Family heights: the doctor estimates a target height from both parents. For boys, add the parents' heights and 5 inches (13 cm), then halve. For girls, subtract 5 inches (13 cm) instead.
3. History and exam: birth size, diet, bowel habits, medicines (especially steroids), puberty stage, body proportions and unusual 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, inflammation markers, celiac antibodies, thyroid function, IGF-1 (a marker of growth hormone activity), and a chromosome test in girls.
6. Specialist tests: growth hormone stimulation testing and a brain MRI if growth hormone deficiency is suspected.

Treatment

• Constitutional delay and familial short stature: usually reassurance and monitoring. Boys with marked delay who are distressed can be offered a short course of low-dose testosterone to start puberty a little earlier. It does not change final height.
• Growth hormone deficiency: daily or weekly growth hormone injections until growth is complete. Starting early gives the best results.
• Other approved uses of growth hormone: Turner syndrome, Noonan syndrome, Prader-Willi syndrome, chronic kidney disease, SHOX deficiency, small for gestational age without catch-up, and idiopathic short stature in selected children.
• Hypothyroidism: daily thyroid hormone tablets, with catch-up growth.
• Celiac disease and Crohn's disease: a strict gluten-free diet, or treatment of the bowel inflammation, often restores growth.
• Nutrition: dietitian support and treatment of feeding problems.

Height-boosting supplements and "growth" products sold online do not increase height and are not recommended.

Frequently asked questions

What causes delayed growth in a child?

The most common causes are normal variants: being a late bloomer (constitutional delay) or having short parents. Medical causes include growth hormone deficiency, an underactive thyroid, celiac disease, Crohn's disease, chronic kidney disease, Turner syndrome and poor nutrition. The growth rate over time helps doctors tell these apart.

Will a late bloomer catch up in height?

Usually yes. Children with constitutional growth delay start puberty late but keep growing for longer, because their bones mature more slowly. Most reach an adult height within the normal range for their family, even though they are shorter than classmates during early adolescence.

What is bone age and why is it done?

Bone age is an estimate of skeletal maturity made from an X-ray of the left hand and wrist. A bone age younger than actual age means more growing time remains, which is typical of late bloomers and some hormone problems. It helps doctors predict adult height and choose further tests.

When should I worry about my child's growth?

See your pediatrician if your child has crossed down two percentile lines, grows less than about 2 inches a year before puberty, is far shorter than expected for your family, or has no signs of puberty by 13 in girls or 14 in boys. Slow growth with headaches, vision changes, diarrhea or weight loss needs prompt review.

Does growth hormone make every short child taller?

No. Growth hormone works well when a child lacks it and helps in certain conditions such as Turner syndrome and kidney disease. In healthy short children the gain is modest, often an inch or two, after years of daily injections, so it is used selectively after specialist assessment.