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Constipation in Children

by Deborah M. Consolini, MD

Constipation is responsible for up to 5% of pediatric office visits. It is defined as delay or difficulty in defecation.

Normal frequency and consistency of stool varies with children's age, and diet; there is also considerable variation from child to child.

Most (90%) normal neonates pass meconium within the first 24 h of life. During the first week of life, infants pass an average of 4 to 8 stools/day; breastfed infants typically have more stools than formula-fed infants. During the first few months of life, breastfed infants pass a mean of 3 stools/day, vs about 2 stools/day for formula-fed infants. By age 2 yr, the number of bowel movements has decreased to slightly < 2/day. After age 4 yr, it is slightly > 1/day.

In general, signs of effort (eg, straining) in a young infant do not signify constipation. Infants only gradually develop the muscles to assist a bowel movement.


Constipation in children is divided into 2 main types:

  • Organic (5%)

  • Functional (95%)


Organic causes involve specific structural, neurologic, toxic/metabolic, or intestinal disorders. They are rare but important to recognize (see Organic Causes of Constipation in Infants and Children).

The most common organic cause is

  • Hirschsprung disease

Other organic causes that may manifest in the neonatal period or later include

  • Anorectal malformations

  • Cystic fibrosis

  • Metabolic disorders (eg, hypothyroidism, hypercalcemia, hyperkalemia)

  • Spinal cord abnormalities


Functional constipation is difficulty passing stools for reasons other than organic causes.

Children are prone to develop functional constipation during 3 periods:

  • After the introduction of cereals and solid food

  • During toilet training

  • During the start of school

Each of these milestones has the potential to convert defecation into an unpleasant experience.

Children may put off having bowel movements because the stools are hard and uncomfortable to pass or because they do not want to interrupt play. To avoid having a bowel movement, children may tighten the external sphincter muscles, pushing the stool higher in the rectal vault. If this behavior is repeated, the rectum stretches to accommodate the retained stool. The urge to defecate is then decreased, and the stool becomes harder, leading to a vicious circle of painful defecation and worsened constipation. Occasionally, soft stool passes around the impacted stool and leads to stool incontinence.

In older children, diets low in fiber and high in dairy may lead to hard stools that are uncomfortable to pass and can cause anal fissures. Anal fissures cause pain with stool passage, leading to a similar vicious circle of delayed bowel movements, resulting in harder stool that is more painful to pass.

Stress, desire for control, and sexual abuse are also some of the functional causes of stool retention and subsequent constipation.

Organic Causes of Constipation in Infants and Children


Suggestive Findings

Diagnostic Approach


Anal stenosis

Delayed passage of stool in the first 24–48 h of life

Explosive and painful stools

Abdominal distention

Abnormal appearance or position of the anus

Tight anal canal detected by digital examination

Clinical evaluation

Anteriorly displaced anus

Severe chronic constipation with marked straining and pain when stool is passed

Typically no response to aggressive use of stool softeners and cathartics

Anal opening not located in the center of the pigmented area of the perineum

Calculation of API* indicating anterior placement, which varies by sex:

  • Girls: < 0.29

  • Boys: < 0.49

Imperforate anus

Abdominal distention

No passage of stool

Abnormal appearance or position of the anus or possibly no anus

Clinical examination

Endocrine or metabolic disorders

Diabetes insipidus



Excessive crying quieted with water intake

Weight loss


Urine and serum osmolality

ADH levels

Serum Na

Sometimes water deprivation test


Nausea, vomiting

Muscle weakness

Abdominal pain

Anorexia, weight loss



Serum Ca


Muscular weakness

Polyuria, dehydration

History of growth failure

Possibly history of aminoglycoside, diuretics, cisplatin, or amphotericin use

Electrolyte panel


Poor feeding


Large fontanelles and hypotonia in neonates

Cold intolerance, dry skin, fatigue, prolonged jaundice

Thyroid-stimulating hormone (TSH)

Thyroxine (T 4 )

Spinal cord defects


Grossly visible lesion in vertebral spine at birth

Decrease in lower-extremity reflexes or muscular tone

Absence of anal wink

Plain x-rays of lumbosacral spine

Spinal MRI

Occult spina bifida

Sacral hair tuft or pit

Spinal MRI

Tethered cord

Change in gait

Pain or weakness in lower extremities

Urinary incontinence

Back pain

Spinal MRI

Spinal cord tumor or infection

Back pain

Pain or weakness in lower extremities

Decrease in lower-extremity reflexes

Change in gait

Urinary incontinence

Spinal MRI

Intestinal disorders

Celiac disease (gluten enteropathy)

Symptom onset after introduction of wheat into diet (typically after age 4–6 mo)

Failure to thrive

Recurrent abdominal pain


Diarrhea or constipation


Serologic screening for celiac disease (IgA antibody to tissue transglutaminase)

Endoscopy for duodenal biopsy

Cow's milk protein intolerance (milk protein allergy)


Diarrhea or constipation


Anal fissures

Failure to thrive

Symptom resolution with elimination of cow's milk protein

Sometimes endoscopy or colonoscopy

Cystic fibrosis

Delayed passage of meconium or meconium ileus in the neonate

Possible repeated episodes of small-bowel obstruction (meconium ileus equivalent) in older children

Failure to thrive

Repeated episodes of pneumonia or wheezing

Sweat test

Genetic testing

Hirschsprung disease

Delayed passage of meconium

Abdominal distention

Tight anal canal detected by digital examination

Barium enema

Anorectal manometry and rectal biopsy for confirmation

Irritable bowel syndrome

Chronic recurrent abdominal pain

Often alternating diarrhea and constipation

Feeling of incomplete evacuation

Passage of mucus

No anorexia or weight loss

Clinical evaluation

Intestinal pseudo-obstruction

Nausea, vomiting

Abdominal pain and distention

Abdominal x-ray

Colonic transit time

Antroduodenal manometry

Intestinal tumor

Weight loss

Night sweats


Abdominal pain and/or distention

Palpable abdominal mass

Bowel obstruction


Cerebral palsy and other severe neurologic deficits

In most children with cerebral palsy, which causes intestinal hypotonia and motor paralysis

Tube feedings with low-fiber formulas

Clinical evaluation

Drug adverse effects

Use of anticholinergics, antidepressants, chemotherapeutics, or opioids

Suggestive history

Clinical evaluation


Infant botulism

New onset of poor suck, feeding difficulties, anorexia, drooling

Weak cry



Descending or global hypotonia and weakness

Possible history of ingestion of honey before age 12 mo

Test for botulinum toxin in stool

Lead toxicity

Most likely asymptomatic

Possible intermittent abdominal pain, sporadic vomiting, fatigue, irritability

Loss of developmental milestones

Blood lead level

*API (anal position index) is calculated as follows:

  • Girls: Distance from anus to fourchette/distance from coccyx to fourchette (normal mean ± SD 0.45 ± 0.08)

  • Boys: Distance from anus to scrotum/distance from coccyx to scrotum (normal mean ± SD 0.54 ± 0.07)

SD = standard deviation.


Evaluation should focus on differentiating functional constipation from constipation with an organic cause.


History of present illness in neonates should determine whether meconium has been passed at all and, if so, when. For older infants and children, history should note onset and duration of constipation, frequency and consistency of stools, and timing of symptoms—whether they began after a specific event, such as introduction of certain foods or a stressor that could lead to stool retention (eg, introduction of toilet training). Important associated symptoms include soiling (stool incontinence), discomfort during defecation, and blood on or in the stool. The composition of the diet, especially the amount of fluids and fiber, should be noted.

Review of systems should ask about symptoms that suggest an organic cause, including new onset of poor suck, hypotonia, and ingestion of honey before age 12 mo (infantile botulism); cold intolerance, dry skin, fatigue, hypotonia, prolonged neonatal hyperbilirubinemia, urinary frequency, and excessive thirst (endocrinopathies); change in gait, pain or weakness in lower extremities, and urinary incontinence (spinal cord defects); night sweats, fever, and weight loss (cancer); and vomiting, abdominal pain, poor growth, intermittent diarrhea (intestinal disorders).

Past medical history should ask about known disorders that can cause constipation, including cystic fibrosis and celiac disease. Exposure to constipating drugs or lead paint dust should be noted. Clinicians should ask about delayed passage of meconium within the first 24 to 48 h of life, as well as previous episodes of constipation and family history of constipation.

Physical examination

The physical examination begins with general assessment of the child’s level of comfort or distress and overall appearance (including skin and hair condition). Height and weight should be measured and plotted on growth charts.

Examination should focus on the abdomen and anus and on the neurologic examination.

The abdomen is inspected for distention, auscultated for bowel sounds, and palpated for masses and tenderness. The anus is inspected for a fissure (taking care not to spread the buttocks so forcefully as to cause one). A digital rectal examination is done gently to check stool consistency and to obtain a sample for occult blood testing. Rectal examination should note the tightness of the rectal opening and presence or absence of stool in the rectal vault. Examination includes placement of the anus and presence of any hair tuft or pit superior to the sacrum.

In infants, neurologic examination focuses on tone and muscle strength. In older children, the focus is on gait, deep tendon reflexes, and signs of weakness in the lower extremities.

Red flags

The following findings are of particular concern:

  • Delayed passage of meconium (> 24 to 48 h after birth)

  • Hypotonia and poor suck (suggesting infant botulism)

  • Abnormal gait and deep tendon reflexes (suggesting spinal cord involvement)

Interpretation of findings

A primary finding that suggests an organic cause in neonates is constipation from birth; those who have had a normal bowel movement are unlikely to have a significant structural disorder.

In older children, clues to an organic cause include constitutional symptoms (particularly weight loss, fever, or vomiting), poor growth (decreasing percentile on growth charts), an overall ill appearance, and any focal abnormalities detected during examination (see Organic Causes of Constipation in Infants and Children). A well-appearing child who has no other complaints besides constipation, who is not taking any constipating drugs, and who has a normal examination likely has a functional disorder.

A distended rectum filled with stool or the presence of an anal fissure is consistent with functional constipation in an otherwise normal child. Constipation that began after starting a constipating drug or that coincides with a dietary change can be attributed to that drug or food. Foods that are known to be constipating include dairy (eg, milk, cheese, yogurt) and starches and processed foods that do not contain fiber. However, if constipation complaints begin after ingestion of wheat, celiac disease should be considered. History of a new stress (eg, a new sibling) or other potential causes of stool retention behavior, with normal physical findings, support a functional etiology.


For patients whose histories are consistent with functional constipation, no tests are needed unless there is no response to conventional treatment. An abdominal x-ray should be done if patients have been unresponsive to treatment or an organic cause is suspected. Tests for organic causes should be done based on the history and physical examination (see Organic Causes of Constipation in Infants and Children):

  • Barium enema, rectal manometry, and biopsy (Hirschsprung disease)

  • Plain x-rays of lumbosacral spine; MRI considered (tethered spinal cord or tumor)

  • Thyroid-stimulating hormone and thyroxine (hypothyroidism)

  • Blood lead level (lead poisoning)

  • Stool for botulinum toxin (infant botulism)

  • Sweat test and genetic testing (cystic fibrosis)

  • Ca ++ and electrolytes (metabolic derangement)

  • Serologic screening usually for IgA antibodies to tissue transglutaminase (celiac disease)


Specific organic causes should be treated.

Functional constipation is ideally initially treated with

  • Dietary changes

  • Behavior modification

Dietary changes include adding prune juice to formula for infants; increasing fruits, vegetables, and other sources of fiber for older infants and children; increasing water intake; and decreasing the amount of constipating foods (eg, milk, cheese).

Behavior modification for older children involves encouraging regular stool passage after meals if they are toilet trained and providing a reinforcement chart and encouragement to them. For children who are in the process of toilet training, it is sometimes worthwhile to give them a break from training until the constipation concern has passed.

Unresponsive constipation is treated by disimpacting the bowel and maintaining a regular diet and stool routine. Disimpaction can occur through oral or rectal agents. Oral agents require consumption of large volumes of liquid. Rectal agents can feel invasive and can be difficult to give. Both methods can be done by parents under medical supervision; however, disimpaction sometimes requires hospitalization if outpatient management is unsuccessful. Usually, infants do not require extreme measures, but if intervention is required, a glycerin suppository is typically adequate. For maintenance of healthy bowels, some children may require OTC dietary fiber supplements. These supplements require consuming 32 to 64 oz of water/day to be effective (see Treatment of Constipation).

Treatment of Constipation

Type of Therapy



Selected Adverse Effects



Oral high-dose mineral oil (should not be used in infants < 1 yr or in neurologically impaired children to avoid aspiration)

15–20 mL/yr of age (maximum 240 mL/day) for 3 days or until stool appears

Fecal incontinence, malabsorption of fat-soluble vitamins (if treatments are repeated)

Oral polyethylene glycol–electrolyte solution

25 mL/kg/h (maximum 1000 mL/h) by NGT until stool appears or 20 mL/kg/h for 4 h/day

Nausea, vomiting, cramping, bloating

Oral polyethylene glycol without electrolytes

1–1.5 g/kg dissolved in 10 mL/kg water once/day for 3 days

Fecal incontinence


Glycerin suppositories

Infants and older children: 1/2–1 suppository once/day for 3 days or until stool appears


Rectal mineral oil enema

2–11 yr: 2.25 oz once/day for 3 days or until stool appears

12 yr: 4.5 oz once/day for 3 days or until stool appears

Fecal incontinence, mechanical trauma

Rectal phosphate Na enema

2– 4 yr: 1.13 oz once/day for 3 days or until stool appears

5–11 yr: 2.25 oz once/day for 3 days or until stool appears

12 yr: 4.5 oz once/day for 3 days or until stool appears

Mechanical trauma, hyperphosphatemia

Maintenance agents

Oral osmotic and lubricant laxatives

Lactulose (70% solution)

1 mL/kg once/day or bid (maximum 60 mL/day)

Abdominal cramping, flatus

Mg hydroxide (400 mg/5 mL solution)

1–2 mL/kg once/day

If overdose, risk of hypermagnesemia, hypophosphatemia, or secondary hypocalcemia

Mineral oil

1–3 mL/kg once/day

Fecal incontinence

Polyethylene glycol 3350 powder dissolved in water

1–18 mo: 1 tsp powder in 60 mL (2 oz) water once/day

> 18 mo–3 yr: 1/2 packet powder (8.5 g) in 120 mL (4 oz) water once/day

3 yr: 1 packet (17 g) in 240 mL (8 oz) water once/day

Fecal incontinence

Oral stimulant laxatives (to be used for a limited period of time)

Bisacodyl (5 mg tablets)

2–11 yr: 1–2 tablets once/day

12 yr: 1–3 tablets once/day

Fecal incontinence, hypokalemia, abdominal cramps

Senna syrup: 8.8 mg sennosides/5 mL

Senna tablets: 8.6 mg sennosides/tablet

> 1 yr: 1.25 mL once/day up to 2.25 mL bid

2–5 yr: 2.5 mL once/day up to 3.75 mL bid

6–11 yr: 5 mL once/day up to 7.5 mL bid

12 yr: 1 tablet once/day up to 2 tablets bid

Abdominal cramping, melanosis coli

Maintenance diet supplements

Dietary fiber supplements


< 6 yr: 0.5–1 g once/day

6–11 yr: 1 g 1–3 times/day

12 yr: 2 g 1–3 times/day

Less bloating than other fiber supplements


6–11 yr: 1.25–15 g 1–3 times/day

12 yr: 2.5–30 g 1–3 times/day

Bloating, flatus

Sorbitol-containing fruit juices (eg, prune, pear, apple)

Infants and older children: 30 to 120 mL (1–4 oz)/day


Wheat dextrin*

2–20 yr: 5 g plus 1 g for each yr of age once/day

Bloating, flatus

*Numerous commercial products and preparations are available in differing concentrations, so doses are given in terms of grams of fiber.

Key Points

  • Functional constipation accounts for about 95% of cases.

  • Organic causes are rare but need to be considered.

  • Delayed passage of meconium for > 24 to 48 h after birth raises suspicion of structural disorders, especially Hirschsprung disease.

  • Early intervention with dietary and behavior changes can successfully treat functional constipation.

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