I'm a paediatric endocrinologist and this is what I'd do if my child isn't growing taller

A child's height should be assessed against their own growth pattern and genetic potential, rather than compared with classmates or cousins. As a paediatric endocrinologist, I explain when slower growth is a normal variation and when it may need medical evaluation.

In Short

• Doctors compare a child's height with genetic potential using parental measurements
• Single readings can mislead, so serial growth records offer better clues
• Normal children follow predictable growth phases from infancy through puberty

As a pediatric endocrinologist, I am often consulted by parents worried about their child’s growth, when their child is shorter than classmates, a younger sibling or a cousin, or simply because one or both parents are short. My response is to counter worry with data. I measure the child and both parents accurately, calculate the mid-parental height (MPH) to assess the genetic potential, and insist on previous growth records. Accuracy and genetic potential are so crucial. After all, a couple who are 4’11” and 5’3” are unlikely to have a 6-foot-tall offspring. That is why I measure parents’ heights whenever possible, rather than relying on impressions, which may be surprisingly wrong.

HOW DO I INTERPRET THE CHILD’S HEIGHT?

When consulted by a family, I need to do some maths. If even this simplified description gets confusing, hang in there. I promise it will get easier as I go along.

I look at the MPH in comparison to adult height in Indian normative data, and the child’s height in comparison to the MPH. For instance, if the MPH is 1 standard deviation (SD) below average adult Indian height, and the child’s height is also about 1 SD below the mean for age and gender, then bingo. This child is normal. Height is inappropriate for the MPH, say MPH is mean + 1.5 SD and the child’s height is mean - 0.5 SD, is worrying and needs thorough evaluation.

THE GROWTH VELOCITY IS FAR MORE IMPORTANT

It’s possible to get misled by a single measurement. The rate of growth is more revealing because children grow within predictable ranges: “rapid, slow, rapid and stop”. This is the Infancy-Childhood-Puberty (ICP) model of growth.

The normal infant gains about half the birth length in the first year of life and a quarter of the birth length in the second year (RAPID). After this explosive growth, the child grows steadily at 5–6 cm/year till puberty starts (SLOW). During 4–5 years of puberty, growth is at 6–9 cm/year (RAPID), and then it STOPS.

A common myth is that children grow till 18 years of age. No! Final height is reached 4–5 years from the start of puberty, so a girl starting puberty at 9 years is done growing by 13–14 years.

No matter how short or tall the parents are, this should be the normal child’s rate and pattern of height gain. You ask: How come? Over 9–10 years, if the short parents’ child grows at 5 cm/year and the tall parents’ child at 6 cm/year, the difference in their final heights would be about 9-10 cm, the difference between a short and tall adult. Makes sense?

REMEMBER, PAEDIATRICS IS THE SCIENCE OF THE GROWING CHILD

Normal growth and development are excellent indicators of good health. It’s amazing how faithfully children track along their own percentile. So please pay attention to your child’s growth from birth onwards.

Have the infant’s length and weight recorded every 3 months, and then height and weight every 6-12 months till final height is reached. Have the numbers plotted sequentially on the growth curve, with your MPH on the right axis.

Monitoring is important for every child, but more vigilance is needed if there is any chronic condition; asthma, nephrotic syndrome, epilepsy, heart or gut ailment, thalassaemia, leukaemia, literally anything.

Paediatricians strongly espouse prevention. Sensible parents shouldn’t ignore this important, yet easily measured, parameter. Deviations from the pattern can be an early warning of trouble. Outcomes are better if problems are tackled before becoming severe.

If your child has subnormal height gain for 6–12 months, is falling off his/her percentile line, or, conversely, is growing too rapidly, you need a pediatric endocrinologist. Carry all the measurements.

BACK TO THE WORRIED PARENTS

With this concerned family, I plot the MPH on the right axis, plot the child’s current and all previous heights and weights, and look at the pattern on the growth curve.

If things are appropriate, I reassure, but don’t just dismiss the matter. I get some tests done to ensure nothing critical is missed, give basic advice about a healthy lifestyle, which is becoming rarer, and emphasise follow-up.

The entire family needs to pay attention to good nutrition, minimal processed food, regular outdoor play, sleep hygiene and attention to mental health. I must balance between not missing a medical issue and not mislabelling or medicalising a normal child.

For a child with inappropriate growth, a detailed workup is necessary.

LET’S BE CLEAR ABOUT WHEN TO WORRY

Who needs evaluation? The child growing slower than 4.5 cm/year before puberty, or 6 cm/year during puberty. The child crossing percentile lines downwards, or whose height is more than 2 SD below the mean for age and gender.

The child born “small for date”, with insufficient catch-up growth by age 2–4 years.

Apart from the growth parameters, the pale child, constantly fatigued, has chronic or frequent diarrhoea or constipation, headaches or changes in vision, or abnormal-looking body proportions.

The adolescent with delayed or slow puberty, or periods that remain irregular even 2 years after starting.

The child with any chronic condition.

WHY ALL THIS FUSS?

Remember the adage: a stitch in time saves nine? Well, it’s true. Early identification and proper treatment of disorders almost always improve outcomes.

Conditions like hypothyroidism, celiac disease or growth hormone deficiency respond very satisfactorily if managed early. Ensuring normal growth may be more challenging with some chronic disorders or medications like corticosteroids and anti-epileptics, etc., but early intervention helps.

In conditions like achondroplasia, where growth retardation is severe and there is no effective treatment, the parents and medical team must offer psychological support and optimise mental health.

The converse deserves another adage: if it ain’t broke, don’t fix it! Quite often, the short child has a normal variation in growth. Is he/she okay by MPH standards? It’s ‘familial short stature’.

Does the child have ‘constitutional delay’, a usually inherited tendency to have delayed puberty? He/she, usually he, is much shorter than peers but catches up when puberty starts.

These situations can be quite devastating for the adolescent and worrying for the family, but require reassurance and attention to general wellbeing: nutritious food, regular exercise, adequate sleep, limited screen time and good mental health. And my watchful eye. Not causing further needless anxiety with endless tests or unnecessary medication.

THE BOTTOM LINE

Monitoring children’s growth through the growing years is highly recommended. Don’t compare them with classmates or cousins, but with their own growth patterns.

When concerned, consult me early, not late; get a baseline assessment and follow up regularly.

(Dr Anju Virmani, Senior Consultant, Pediatric Endocrinology, Madhukar Rainbow Children’s Hospital)

- Ends