Is my child too short? When to get a growth check

Parents often worry when their child is the shortest in class. Most of the time the child is healthy: short parents tend to have short children, and some children simply start puberty later and catch up afterwards. But slow growth can also be the first sign of a hormone or medical problem, and some treatments only work while the bones are still growing. So it's worth knowing when to check.

Signs that need a growth assessment

• Your child is much shorter than most children of the same age and sex (below the 3rd percentile on a growth chart)
• Your child is growing slowly: less than about 4 to 5 cm a year between age 3 and the start of puberty
• Your child is dropping across growth chart lines over time
• Your child is much shorter than expected from the parents' heights
• Short stature comes with other signs: poor appetite, tummy problems, tiredness, delayed puberty, unusual body proportions, or learning difficulties

The growth rate matters more than a single height. A child who is short but growing steadily along their own curve is usually fine. A child whose growth slows down needs checking, even if their height is still "normal".

Estimate the expected adult height

Doctors use the parents' heights (in cm) to estimate a child's target adult height:

• Boys: (father's height + mother's height + 13) ÷ 2
• Girls: (father's height + mother's height − 13) ÷ 2

Most children end up within about 8 cm above or below this number. For example, if the father is 170 cm and the mother is 155 cm, a son's target is about 169 cm and a daughter's about 156 cm.

Common causes

• Familial short stature: healthy children of short parents who grow normally and reach a height close to their target.
• Constitutional delay: late bloomers who are short in childhood, enter puberty late and catch up later. There is often a parent who also matured late.
• Nutrition and chronic illness: undernutrition, anaemia, celiac disease, kidney disease and poorly controlled asthma all slow growth.
• Hormone problems: an underactive thyroid, growth hormone deficiency, or long-term steroid use.
• Genetic conditions: Turner syndrome in girls is important to recognise, since it is easily missed and treatment helps. Other conditions include skeletal disorders and syndromes.

What happens at a growth clinic

1. Accurate measurements: height, weight and body proportions, plotted on an Indian growth chart (IAP charts).
2. Bone age X-ray: an X-ray of the left hand shows how much growth is left.
3. Blood tests as needed: blood count, thyroid, kidney and liver function, celiac screen, and IGF-1. In girls, chromosome testing (karyotype) is sometimes needed.
4. Growth hormone stimulation tests, only when growth hormone deficiency is suspected.

Treatment

Treatment depends on the cause: treating the underlying illness, thyroid replacement, nutrition support, or daily growth hormone injections, prescribed by a pediatric endocrinology specialist, for conditions where they are proven to help, such as growth hormone deficiency and Turner syndrome. Growth hormone works only while the growth plates are open, which is why early assessment matters. Healthy children who are simply short do not need hormone treatment.

What parents can do now

• Measure height every 6 months, at the same time of day, against a wall
• Keep school health records
• Make sure your child eats enough protein, has good sleep and is physically active
• Avoid "height increase" supplements, which have no proven benefit

Written by Dr. Prasadh Rao L, MBBS, MD (General Medicine), DM (Endocrinology). Assistant Professor of Endocrinology, Madras Medical College. Tamil Nadu Medical Council Reg. No. 96520.

This article is for general information. It is not a diagnosis or a treatment plan. Please don't start, stop or change any medicine without speaking to your doctor.