The capacity to grow and develop is the essence of the human child, and it's frequently assessed by family, friends and health professionals.

As soon as a new baby arrives in the world, one of the first things everyone wants to know is how much does he or she weigh? From that point on, there are constant enquiries about the child's weight and height.

• Causes of failure to thrive
• Inadequate diet: not enough food being offered or not enough food being taken
• Genetic influences, such as genetic disease
• Low birth weight
• Repeated childhood illness
• Malabsorption
• Chronic disease, for example, kidney failure, malaria, TB
• Emotional deprivation

Breastmilk
Newborn babies should thrive on breastmilk - it's the best choice. But many new mothers and their babies struggle to latch on properly and get a good technique going. Get more advice on breastfeeding from your health visitor.

Formula milk
Despite being second best for other reasons, babies should thrive on formula milk. If your baby isn't growing as they should, you must check that you're following the manufacturer's instructions for making up the feed exactly (not too dilute), and that your baby is able to get the milk as fast as it needs to (check the teat size).

Children may be unable to absorb food into their body because of problems with their gut
Coeliac disease, which causes diarrhoea with foul-smelling faeces, anaemia, and failure to thrive, is because of a reaction to gluten (a protein found in wheat and similar proteins in other grains). A lifelong gluten-free diet is usually necessary. Find out more from Coeliac UK.

Things to remember

• Keep a regular eye on your children's growth
• Don't forget, small parents tend to have small children
• If your baby isn't growing, or if you're worried about feeding, talk to your health visitor or GP
• Follow instructions exactly when making up formula feeds
• Ensure your child has a healthy balanced diet

Genetic causes
There are many different inherited conditions that can mean a child fails to thrive, such as chromosomal problems.

Most common of all, accounting for about 80 per cent of small children, is not an illness but simply that the parents are also small. So it's normal for that family. This is sometimes known as constitutional short stature and, of course, no treatment is needed.

What's important is that the child is growing at a steady rate, following a line on the growth charts parallel to the average child, even if continually smaller than average.

If growth slows or stops, then it should be investigated. Trying to feed up a small child is likely to make them chubbier rather than taller.

Failure to thrive may start in the womb
Growth begins in the womb, and some children born with a low weight as a result of some factor in the pregnancy will continue to have problems catching up. This is more likely if the growth retardation happened early in the pregnancy.

If a mother has high blood pressure, smokes, drinks alcohol or takes certain medications, it can affect a baby's growth before it's born. Maternal infections, such as rubella and toxoplasmosis, can also result in a low birth weight baby.

Any illness in a child temporarily slows growth
Serious illness is more likely to affect growth, from chronic infection such as TB to major heart abnormalities, deficiencies of hormones such as thyroid or growth hormone, lung diseases such as cystic fibrosis, and kidney disease.

Psychological problems
Sometimes there's no apparent physical explanation for why a child is failing to thrive until home circumstances are carefully probed. Social deprivation, especially if a child's emotional needs are being neglected, can lead to growth problems even in the first few months of life.

While poverty increases the risk, a big house stuffed with toys doesn't, on its own, guarantee that a child is happy and emotionally nourished.