As a paediatric doctors, we see many parents who are worried about their children being short for their age. To begin with it is good to understand that there is a wide range in what we consider normal. Health care workers use standardised growth charts to determine how tall children are compared to other kids their age.
For babies and toddlers up to 24 months we use the World Health Organisation (WHO) growth charts and for children 2 and older we use the Centres of Disease Control and Prevention (CDC) growth charts. There are free versions of these charts available on the internet.
We often talk about percentiles when we compare children to a typical population for their age. If someone is on the 1st percentile it means that 99% of children of the same sex and age are taller than them. If someone is on the 90th percentile it means that 90% of kids their age are shorter than them and only 10% of kids their age are taller than them.
Many factors are involved in normal growth. These include countless genes as well as hormones, nutrition, health or illness, puberty and the child’s environment. Examples of reasons for short stature include; familial short stature, constitutional delay in growth and development, medical problems, syndromes, other genetic causes, hormone problems, bony dysplasias, side effects of medications and failure to thrive. Rarely emotional deprivation can cause growth problems.
Familial Short Stature
In general, tall parents will have tall children and short parents will have short children. Doctors will normally ask about the height of each biological parent. We calculate an average of the parents’ heights and correct this for the sex of the child. We call this the mid-parental height. If the mid-parental height is on the first percentile then we would not expect the child to be tall or even average height.
Constitutional Delay in Growth and Development
This is a normal variant. These children will be short during the childhood years, start puberty later than average then have a later growth spurt and eventually catch up to their peers. There is often a family history eg the mother starting periods later than average or the father growing after finishing school. This was discussed previously in PUBERTY IN GIRLS and PUBERTY IN BOYS.
A lot of chronic diseases or their treatments will affect growth. Examples include cystic fibrosis, severe congenital heart problems, juvenile idiopathic arthritis and gastrointestinal disorders such as inflammatory bowel disease.
Children with chromosomal differences such as Down syndrome (an extra chromosome 21) or Turner syndrome (girls missing part or whole of one of their X chromosomes) will typically be short. There are a number of syndrome-specific growth charts available.
Other genetic causes
Many other syndromes and genetic abnormalities are associated with short stature. These include Russell-Silver syndrome, Noonan syndrome and Prader-Willi syndrome.
Endocrine (hormone) problems
Interestingly, most hormone problems affecting growth tend to make children short and relatively overweight rather than short and underweight. They include growth hormone deficiency, under-active thyroid, pituitary gland problems, Cushing syndrome and pseudohypoparathyroidism.
Achondroplasia is probably the best known of these conditions but there are many genetic abnormalities that affect the growth of long bones such as those in our arms and legs. People with bony dysplasias often have disproportion eg short limbs but normal length trunk.
Medications and other treatments
Some medications such as high doses of potent corticosteroids eg prednisolone will affect growth. In some cases, children will experience catch up growth after they are able to be weaned off the drug. Several medications used for ADHD can also affect growth, primarily due to suppressing appetite. Previous radiotherapy to the brain or spine may also affect growth.
Failure to thrive
Children who are struggling to gain weight due to chronic disease, malabsorption or through simply not eating enough will often grow slowly. We distinguish these causes from other causes of short stature as helping nutrition will often result in an improvement in growth.
Assessment of the child with short stature
If you are worried about your child’s growth then take them to see a doctor. Your doctor will probably do a number of things to determine whether there is a problem and if so what to do about it.
History (what they ask you) will include the child’s birth history, medical problems, medications and other health issues. They may ask about symptoms relating to specific diseases. They will also ask about your height and your partner’s height to determine what is normal for your family.
- Height – to be accurate this must be measured without shoes and socks using a stadiometer. We then plot the height on the appropriate growth charts. This can be reassuring if the child’s height is in the normal range.
- Growth trajectory using previous measurements. Are they growing steadily or slowly? If they are growing slowly they will be “crossing centiles” eg going from the 5th percentile to the 3rd percentile to the 1st percentile etc.
- Weight – knowing whether a child is short and underweight or short and relatively overweight may help narrow down the problem.
- Look for features that may be typical of syndromes associated with short stature eg low hairline at the back and webbed neck in Turner syndrome or a curved little finger in Russell-Silver syndrome.
- Nutrition – fat stores and muscle bulk
- Signs of chronic disease – some of these can be found in the nails, skin, eyes and mouth.
- Major systems eg examination of heart, lungs or gastrointestinal system
- Proportions – eg arm span, sitting height and the ratio of the upper half to lower half of the body.
- Puberty (if relevant)
Investigations and specialist help
If your child is short for the population, much shorter than expected for the family or is growing very slowly then your doctor may do some tests looking for some of the conditions I have mentioned. Your doctor may refer your child to a General Paediatrician (like Dr Megs), particularly if they seem to have an underlying medical problem or failure to thrive. If your child is extremely short (eg shorter than the first percentile) your doctor may refer them to a Paediatric Endocrinologist (like me). In most cases either no treatment is needed or we advise to treat the underlying problem that is affecting growth. In rarer cases we consider treating with growth hormone.
Many children who seem to be short are completely healthy and their height is within the normal range for the population. However, if you are concerned about your child’s height compared to their peers or your family or if you think they are growing slowly then make an appointment to see your doctor.
Till next time,