Constipation in childhood is one of the most common concern that brings parents to hospital. As a paediatrician the number of constipation cases that I see in OPD in daily practice is insane. Data states that, 1 out of every 3 kids visiting paediatric gastroenterologist is suffering from childhood constipation. 


Constipation definition:

You say it is constipation when, 

  1. There is less frequent passage of stool i.e. less than 3 times a week,
  2. Along with stool is dry and hard in consistency. 


So in lay man’s language constipation is when there is delay as well as difficulty in passing motion. 

When and How constipation in childhood presents ?

Constipation in childhood can show up during either of following phases of life

  1. At weaning breast milk
  2. At beginning of toilet training 
  3. At School age 

It characteristically presents with tummy pain, poor oral intake of food, difficulty in passage of stool, soiling of pant etc.


How food passes through gut?

Before trying to figure out why constipation happens so commonly in kids, let us understand normal mechanism of bowel movement.

Food passes from mouth, to oesophagus and then to stomach. Thereafter it moves through small intestine, en route towards large intestine. And finally it comes out via anus. As food travels, it mixes with gut secretions and gets digested along its path.

The most distal portion of large intestine is called rectum. As stool collects here, it distends rectum wall. This stimulates rectum to contract and push stool out across anus, as the later relaxes. 

Below 3 factors governs, how smooth movement of bowel is going to be.


  1. Bulk of food
  2. Gut wall muscle activity 
  3. Rectum and anus reflex 


Gut, is gateway to good health. For rest other systems to function properly, gut had better be be healthy. This is the importance of digestive system and bowel movement.


If your kid is going through constipation too, then you are at the right place. Because here in this article we will dig out the root causes of hard stool and constipation in childhood.


1.Functional or psychogenic

Constipation in childhood triggers panic in parents. But truth to be told, around 90-95% constipation cases are functional constipation. 


Here, there is no underlying organic cause. In other words child doesn’t have, 


  • any structural abnormality of gut that needs surgery or 
  • any biochemical / hormonal imbalance or 
  • any nerve or muscle dysfunction. 

How do you identify functional constipation?

No expensive investigation is required to diagnose functional constipation.

If symptoms of a child meets Rome IV criteria, then it is entitled as functional constipation. Your paediatrician is the right person to assess, whether constipation is functional or organic.

Why functional constipation happens ?

Most cases of functional constipation in childhood occurs due to stool-withholding behaviour. Child refrains to go to toilet. Stool keeps on accumulating in rectum. Subsequently water is absorbed out of it, leaving behind a dry and hard faecal mass in rectum. This leads to constipation.

Over time as child continues to ignore rectal sensation, rectum becomes less sensitive to fullness. Hence constipation eventually becomes chronic or long lasting. 

Early detection and treatment of constipation maximises benefit.


What is typical presentation of functional constipation ? And when should you worry?

Functional constipation usually presents after infancy. Here the child is well thriving i.e. s/he has adequate gain in weight and height as per age. Apart from infrequent and hard stool, child will face intermittent soiling of underpants, due to rectal overload. Soiling is a peculiar feature of functional constipation. 

But if a child is having actual constipation since birth, or is not able to gain weight and height adequately as per age, then other alternative organic causes should be ruled out. There are certain red flag signs of constipation. If even one of these sign is present then child needs medical attention right away. 



Junk foods like burger, noodle, pizza, biscuits, chips lack soluble and insoluble fibre. In contrary these are loaded with refined and processed sugar, cheese, preservatives to make these tasty. Because of which, it takes longer for these foods to travel across gut. 

Also white rice, white bread, artificial juices are couple of low fibre foods which kids consume on day to day basis. These food also are poor in fibre content. 

Fibre is an integral part of diet that absorbs water and swells up. It makes food bulky, soft and easy to pass. Fibre-less foods are likely to cause constipation


Often it happens that kids consume pretty less water than required. Water keeps stool bulky, soft and moist and helps in easy passage of stool. Paucity of water produces dry hard stool, and hence constipation. 


Constipation in childhood is a self perpetuating viscious cycle. When a child suffers from it, stool becomes very hard and dry. This brings about painful bowel evacuation. 

Pain induces fear of passing stool. Child voluntarily withholds stool, which further worsens constipation. And the cycle continues.

5.Physical activity

Physical activity is something that promotes bowel movement and clearance. In post covid era we see lot of kids spending most part of day indoors without much physical activity. This contributes to constipation. 

6.Cow milk

You will be surprised to know that there is a condition called occult cow milk intolerance. In overt cow milk intolerance, a kid presents with loose motion and vomiting after having cow milk. 

But in occult cases child develops constipation after having cow milk. 


7.Skeletal muscle weakness

For smooth passage of stool, muscle of abdomen should contract and muscle inside anus ( anal sphincter ) and muscles surrounding anus ( pelvic floor muscles ) have got to relax. This doesn’t happen in conditions of skeletal muscle weakness. 

As abdominal and pelvic floor muscles belong to  group of skeletal muscles, any disease affecting skeletal muscle for example “muscle dystrophy” sets off in-coordination of muscle movement and constipation. 

8.School bathroom hygenie

Many a times when a child sets out to go to school, s/he voluntarily withholds going to toilet. This may be because of poor hygiene, or shyness, or lack of leisure break. 

9.Cathartic abuse

This happens in “anorexia nervosa”, which is an eating disorder seen in adolescent girls. Here child is highly guilt-ridden of taking food and gaining weight. 

These kids sometimes use laxative medication on their own. On short term use, laxatives cause diarrhoea. However long term laxative abuse ( cathartic abuse ) brews constipation. 


On occasions certain medications induce constipation. These are listed below


  • antispasmodics
  • anti motility
  • calcium
  • iron
  • antihistaminic
  • codeine containing cough syrup
  • anti cancer ( e.g. vincristine ) 
  • antidepressant
  • narcotic


Kids deficient in thyroid hormones have sluggish bowel movement. This is an intrinsic hormonal condition leading to constipation. 

12.Surgical causes

Occasionally constipation in childhood happens due to obstructive conditions that ultimately need corrective surgery. Few examples of surgical causes of constipation are spelled out here.

  • Fibrosis / stricture / narrowing of gut
  • Tumour in gut
  • Volvulus of intestine – When intestine twists around itself
  • Anterior ectopic anus – Anus is placed at abnormal position
  • Stenosis/ narrowing of anus
  • Pre-sacral teratoma – A tumour arising from lower spine or tail bone that obstruct bowel
  • Anal fissure – A painful tear around anus 
  • Piles / haemorrhoids – Swollen veins inside or around anus 
  • Perinatal abscess – A pocket of pus around anal area.

13.Ganglion defect

Nerve ganglions supply smooth muscle of gut wall and coordinate gut wall movement. In nerve ganglion defects, gut movement slows down.

One such classical example is Hirschsprung’s disease where ganglions is absent from the time of birth. This results in severe intractable constipation since birth. 

14.Spinal cord defect

Spinal cord supplies nerve to bowel. In spinal cord defects, bowel will not move effectively. This is called “neurogenic bowel”. This results in constipation.

This results in constipation. Typical history is of a kid having constipation since birth and child is persistently dependent on laxative. 

So if there is tuft of hair or dimple or swelling present over lower back/ spine , and child is enduring chronic constipation, then spinal cord defect needs to be ruled out. 

15.Electrolyte imbalance

Electrolyte imbalance like hypercalcemia ( increase in blood calcium level ) and hypokalemia ( decrease in blood potassium level ) hinder gut movement. This may cause constipation too. 

16.Sphincter dysfunction


In sphincter dysfunction, anal sphincter doesn’t function accordingly, causing constipation.


Irritable Bowel Syndrome, for the most part, presents as loose motion. But less often it is of constipating type too. 

18. Caeliac disease & IBD

Caeliac disease or caeliac sprue is a condition where gut of an individual can not tolerate gluten-based-foods like wheat, rye, barley etc. Though classic symptom is diarrhoea, it may occasionally turn up as constipation in childhood as well.

Crohn’s disease is a kind of IBD ( inflammatory bowel disease) prevalent in western countries. Here patient falls ill with bouts of severe diarrhoea. Nevertheless, IBD can manifest as constipation as well.

19.CNS abnormalities

A child with central nervous system abnormalities for example a CP child ( child with cerebral palsy ) gets constipation recurrently.


CP child is someone with aberrant muscle movement and posture. Cerebral palsy happens due to insult to growing brain before, during or after delivery. 



Some metal poisoning like arsenic, mercury and minerals lead poisoning leads to constipation. Though it is rare, but is a possibility. Especially chronic lead poisoning which can ensue even with traces of lead.


21.Smooth muscle disease

Muscle in gut wall belongs to group of smooth muscles. This play a fundamental role in propelling food. In diseases of smooth muscles for instance scleroderma, smooth muscle will not contract properly causing constipation. 


22.Metabolic diseases

There are certain diseases of metabolism present since birth. These are called metabolic diseases. One such example is cystic fibrosis. Here gut secretions tends to thicken and cause constipation.

Likewise diabetes is also an acquired metabolic condition that may have constipation as one of its symptoms. 


We have already outlined under cathartic abuse, how kids with eating disorders like anorexia nervosa might show up as constipation following excessive consumption of laxative. 

Important note :

Discontinuing wheat or milk on your own as parent is not at all advisable. Self judgement and treatment may turn against child’s normal growth and development. Take expert’s advice instead. 


If you have read the article and come this far then congratulations. Now you know in depth about reasons why childhood constipation happens and why is it so frequent. 


Do share this in depth article and spread awareness among friends and relatives. 


All the information provided here are for educational and awareness purpose only. Kindly do not use these as alternative to medical consultation.

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