Is my child too short? Growth charts, parents' height and when to worry

“He is the shortest in his class.” “She has not grown at all this year.” Worries about height are among the most common reasons parents see a paediatric endocrinologist. The good news is that most short children are perfectly healthy. The key is to tell normal variation apart from a growth problem, and to do it early.

How do doctors decide if a child is short?

Height is judged against other children of the same age and sex, using growth charts. In India, the Indian Academy of Pediatrics (IAP) recommends:

• WHO growth charts for children under 5 years
• IAP 2015 growth charts for children from 5 to 18 years, which are based on Indian children

A child’s height is plotted as a percentile. The 50th percentile is average. A child is usually considered short if their height is below the 3rd percentile, which means shorter than 97 out of 100 children of the same age and sex.

A single measurement says less than a series. What matters most is the pattern over time. A healthy child usually grows along their own percentile line. A child who keeps dropping to lower lines, called “crossing centiles”, needs review even if they are not yet below the 3rd percentile.

How do the parents’ heights help?

Children usually end up near a height set by their parents. Doctors estimate a target height, also called mid-parental height:

• for a boy: add the father’s and mother’s heights in centimetres, add 13, and divide by 2
• for a girl: add the father’s and mother’s heights in centimetres, subtract 13, and divide by 2

Most children end up reasonably close to this target, though the estimate is rough and some healthy children land well above or below it. A child who is short but tracking towards a short family target is less worrying than a child from tall parents who is far below their expected range.

How should I measure my child?

• Measure without shoes, standing straight against a wall, with heels, buttocks and the back of the head touching it.
• Use a flat book or ruler on top of the head, at a right angle to the wall, and mark the spot.
• Measure at the same time of day, every six months or so, and keep a record.
• Take this record, and old school or clinic measurements, to the doctor.

Weight matters too. Use the BMI calculator for children over 5 years.

What are the common causes of short stature?

Normal variants, the most common causes:

• familial short stature, where short parents have a short but healthy child who grows at a normal rate
• constitutional delay of growth and puberty, the “late bloomer” who is short in childhood, enters puberty late and catches up later. Read early or late puberty.

Causes that need attention:

• poor nutrition or low calorie or protein intake
• chronic illness, including coeliac disease, which is common in parts of India and can cause poor growth even without obvious belly symptoms, as well as kidney, heart, lung or bowel disease, and poorly controlled diabetes
• underactive thyroid. Read high TSH and low T4.
• growth hormone deficiency
• Turner syndrome in girls, a chromosome condition that every unexplained short girl should be checked for
• being born small for gestational age and not catching up by about 2 to 4 years of age
• long-term steroid medicines, including some asthma or skin treatments in high amounts
• skeletal dysplasias, conditions affecting bone growth, often with short limbs or unusual body proportions

When should my child see a paediatric endocrinologist?

Consider a referral if your child:

• is below the 3rd percentile
• is crossing percentile lines downwards
• is growing slower than expected for their age, as judged by your doctor from measurements taken several months apart
• is much shorter than their target height
• has signs of illness, unusual body proportions, or delayed or very early puberty

Earlier is better. Some treatments work only while the growth plates in the bones are still open.

Which tests might be done?

Your doctor will decide based on the history and examination. Common tests include a blood count, kidney and liver tests, a coeliac antibody test, thyroid tests, a karyotype (chromosome test) in girls, and an X-ray of the hand for bone age. If growth hormone deficiency is suspected, IGF-1 is usually checked first, followed by a stimulation test. A single random growth hormone level is not useful, because growth hormone is released in pulses.

What about growth hormone and height supplements?

Growth hormone treatment is effective for specific conditions, such as growth hormone deficiency, Turner syndrome and some children born small who have not caught up. It is a prescription treatment that a paediatric endocrinologist starts and monitors after proper tests. It is not meant for healthy children who are simply short because of family height.

Health drinks, “height-increasing” powders, ayurvedic or homeopathic products marketed for height have no good evidence of increasing adult height. Good nutrition, enough sleep, physical activity and treating any underlying illness are what support a child’s growth potential.

What should I ask the doctor?

• Is my child’s height within the expected range for our family?
• Is my child growing at a normal rate?
• What is the bone age, and what does it mean for final height?
• Are any tests or treatment needed now?

For an assessment by an endocrinologist, book a consultation or read who an endocrinologist is.