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

In this article

What is it? What causes it? Problems with milk feeds

Dietary problems Genetic causes Problems in the womb

Chronic or repeated illness Psychological problems

From the moment they're born, a baby's weight and height are closely monitored. Health visitors provide health record booklets that include growth charts to help with this.

Some children don't grow or gain weight as they should. This is known as 'failure to thrive' and may be caused by a variety of factors. Some children who fit this category appear lethargic, pale and miserable, while others seem fairly well.

In the UK, where chronic disease in childhood isn't common, failure to thrive in infants may be a result of poor feeding techniques.

In older children, unhappy home circumstances and emotional problems are often to blame.

Breastmilk is the best choice for newborns and babies should thrive on it. But some new mothers and their babies struggle to latch on and get a good technique going. Health visitors can offer advice on this and appropriate formula feeds, if necessary.

If you're formula feeding but your baby isn't growing as they should, check 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 they need to (check the teat size).

Children may be unable to absorb food into their bodies because of problems with their gut, such as parasitic infections, malabsorption, liver disease or milk sensitivity (usually temporary).

Coeliac disease, which causes diarrhoea with foul-smelling faeces and anaemia, is another explanation for failure to thrive. It's caused by a reaction to gluten, a protein found in wheat and similar proteins in other grains.

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

The most common of all genetic factors isn't an illness but simply the fact 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.

Some children born with a low weight as a result of some factor during pregnancy will continue to have problems catching up. This is more likely if the growth retardation happened early in the pregnancy.

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

Any illness in a child temporarily slows growth. While many catch up, repeated illness, even coughs and colds, can affect growth in the long term.

Serious illness is more likely to affect growth, from chronic infections 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.

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.

This article was last medically reviewed by Dr Rob Hicks in November 2007