Why is my child not growing properly?

As a parent it’s natural to worry if your child isn’t growing as fast as you would expect, or is falling behind their friends at school. While in many cases short stature is due to short parental heights, some children can be affected by conditions that interfere with their normal growth. In this article leading endocrinologist Dr Helen Spoudeas explains what these conditions are, and whether undernutrition plays a role.

What are the most common causes of growth failure?

The three most common causes of growth failure aregrowth hormone deficiency, skeletal dysplasias and delayed puberty.

Less commonly, growth failure can be caused by a lack of nutrition at a very early age, including in the womb. This is usually associated with a failure to thrive (gain weight appropriately).

Growth hormone deficiency

Growth hormone (GH) is one of the hormones made in the pituitary gland, sited in the deep midbrain and controlled by the hypothalamus above. Failure to produce growth hormone could mean:

• a genetic problem – from isolated cases of GH gene deletion or transcription defects causing pituitary maldevelopment to syndromes such as Prader-Willi syndrome; Genetic Turner’s syndrome results in skeletal dysplasia but we now know it is not a GH deficient (but GH resistant) state.
• a physical problem – such as a tumour within, or pressing on, the gland, or a brain injury which has compromised its function over time.

Aside from removing any tumours that are present, growth hormone deficiency itself is easy and rewarding to treat – it simply involves taking daily hormone injection supplements to make up for the lack of growth hormone in your body.

Skeletal problems

Skeletal problems can also be thought of as “growth-hormone resistant” conditions. In other words, certain parts of your body, such as your limb bones or spine, disproportionately fail to respond to the normal growth hormone production levels. This means that growth hormone supplements are not as effective – no matter how much you take, your bones are unlikely to respond. Thus the only skeletal dysplasia for which growth hormone treatment is licensed is Turner syndrome, but the doses used have to be much higher than a natural replacement for much smaller benefit.

In some cases this condition is known as dwarfism. Some of the most common skeletal problems associated with short stature include Achondroplasia and Hypochondroplasia.

Delayed puberty

About 3 in every 100 children will experience delay in the onset of puberty. Puberty is a process which takes several years to complete. If your child hasn’t shown any sign of breast budding (girl), testicular enlargement (boy) or pubic hair by the age of 14, it’s a good idea to see a doctor. Delayed puberty is a particularly common cause of growth failure in boys of this age. It is often straightforward to treat with sex hormones (oestrogen or testosterone) to trigger puberty. However, sometimes it can result from underlying causes which need their own investigation and treatment.

Lack of nutrition

Throughout pregnancy and the first year of life, nutrition is essential for growth. Failing to get adequate nutrition will tend to leave you permanently shorter through life. However, it’s equally important not to overfeed a baby, as this can actually make you both too tall and too heavy later in life.

By contrast, beyond this first year, it’s difficult to compromise growth rate through malnutrition . Still, malnutrition and failure to thrive in childhood tends to lead to delayed puberty and growth problems if it remains unaddressed.

If you’re worried about your child’s growth, it’s important to visit a doctor – ideally an endocrinologist with a specialty in growth disorders. As you’ve seen, many of the causes of short stature can be treated – but assessment and any treatment needs to start earlier rather than later and may need interim review at crucial periods of maturation.