Constipation in toddlers

General medical advice only ... If you are ever concerned about your child's health, see a doctor.
General medical advice only ... If you are ever concerned about your child's health, see a doctor. 

Until the moment parenthood arrives, few people would anticipate how much time and concern could be generated over the bowel habits of a small child. Constipation is a very common problem which can be caused by a number of of circumstances.

I recently treated Master G, a two-year-old who had developed significant constipation following a bout of fever and vomiting at the age of one. During that time he only passed one hard stool, and on returning to good health he still had infrequent, hard painful stools.

There was also Miss T, a 3½ year old girl who had become significantly constipated since toilet training at the age of 2½. Before this, her stools had been firm but regular, but once she was toilet trained she started to hold on, and would disappear when she needed to go. She started to complain of sore tummies and go off her food in the days leading up to a stool, which could be up to a week apart. At times she would also pass some loose stool in her pants.

Although these children had different habits and causes for their problem, each had constipation.

A normal bowel habit is generally considered to be the passage of soft stool at least every second day, and also without incontinence in children who were previously toilet trained. Incontinence (or soiling) often happens when there’s leakage of wet stool around retained hard stool.

What causes constipation?

In the majority of children with constipation, there’s no major serious underlying cause, particularly if they're still growing well. In some children the onset can be tied to an event, such as the introduction of cow's milk in the first example above, or the period of illness in Master G, but this is by no means universal.

In many children, constipation means that the passage of stools is painful, at times causing bleeding. This often leads to the child holding on, which makes the constipation worse.

Other signs that there may be something more complicated than simple constipation going on include weight loss or poor growth, lower energy levels, and significant straining on the toilet, even when the stool is soft. 


In some cases, constipation can be caused by not having enough fruit and vegetables. The recommended daily intake of fruit and vegetables, a major source of fibre, is five to six servings – a serving size can be held on the palm of the child's hand.

Another problem is excessive milk, and there are two reasons for this. Firstly, cow's milk protein makes some children prone to constipation. Secondly, milk is a calorie-rich food, so drinking too much can lower a child's appetite for solid, fibre containing food.

However, in spite of attention to diet, constipation remains a problem with many children.

How it all works

Think of the gut as a long muscular tube. It pumps food through the body, allowing digestion and eventual elimination of waste. The time from eating an item of food till the elimination of the resulting waste should be less than 48 hours.

The gut is basically divided into two halves: the top half’s main job is to absorb nutrients, and in the majority of children with constipation there’s no problem with absorption. Stool at the half way mark (at the bottom of the top half of the gut) is runny in everyone, whether they have constipation or not.

Then the stool enters the lower half of the bowel, whose main job is to reabsorb water back into the body. This is what makes the stool which is eventually passed out of the body not so runny. Usually constipation means the stool takes too long to pass through the lower part of the bowel, making it more and more dry, and larger in size. This stretches the muscular wall of the lower bowel – and because stretched muscle doesn't pump well, the problem gets worse.

Treating constipation in young children

Once a child has been constipated for some time, the best way to break this cycle is to have the child on the level of daily laxative that normalises their stool habit. You’ll know within two or three days whether the current dose of laxative is working. 

Your child will need to be on the laxatives for a minimum of three months – this is how long it can take for the stretched muscle of the lower gut to gradually get back to normal size, so it can pump more effectively again.

The usual laxatives for kids are harmless and don't cause reliance, and they should be kept up until your child has normal bowel habits (that is, a stool soft enough that your child can't abnormally hold on, at least every second day).

Fortunately most children do eventually grow out of constipation, provided there is effective treatment. And just remember: the sooner the child gets onto effective treatment, the sooner the problem will go away.

Robyn Shaw is a specialist paediatrician involved in the medical care of babies and children of all ages. She is in private practice in Wellington, and also has long experience in public hospitals within New Zealand and Australia. 

- © Fairfax NZ News

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