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Functional Constipation in Children

By Danel Tainton, Specialist Paediatric Dietitian

6 mins
Upset toddler having tummy troubles


Functional constipation (FC) is common in childhood and has been reported to affect up to one-third of children1. In a large proportion of children constipation presents in the first year of life2.

The most likely triggers for FC are:

  • Progressing from breastmilk to formula milk or weaning
  • Starting nursery or school
  • Potty training

These may result in firmer stool consistency, the altered sensation when passing stools or stool withholding, which trigger a cycle of large, difficult to pass stools, pain, fear and further stool withholding.

Other precipitating factors may include medications (such as Sodium alginate therapy used for the treatment of reflux), existing medical conditions (neurological conditions such as cerebral palsy are associated with gut dysmotility) or social circumstances (history of abuse or neglect).

Identification of Functional Constipation

The diagnosis of FC is based on the ROME IV criteria for functional gastro-intestinal disorders2. In a clinical setting, constipation is identified by the presence of one or more of the following symptoms1.

  • Passing less than three type 3 or 4 stools per week (Bristol stool chart)
  • Small hard stools resembling rabbit droppings (type 1 Bristol stool chart)
  • Difficulty or straining to pass stools
  • Pain or distress during defecation
  • Large stools in the rectum or passing of stools so large it obstructs the toilet
  • Soiling which may occur throughout the day and can be mistaken for, or result in incontinence

Management of constipation in children and infants

Early intervention and treatment can improve outcomes. Functional constipation is known to exacerbate existing conditions such as reflux and epilepsy and may even reduce appetite. In the long-term untreated FC can negatively impact quality of life, school performance, social interactions, nutritional status and growth.


The National Institute of Health and Care Excellence (NICE) recommends first-line treatment with Macrogols1 (Movicol or Laxido) and disimpaction may be required to clear the bowel before maintenance therapy can be effective.

Parents often hesitate to start laxatives as they are concerned that the bowel would become “lazy” and dependant on laxatives. It is important to provide reassurance that laxatives such as Macrogols are natural stool softeners and lubricants that help stool move through the bowel. Delaying laxative therapy or poor compliance can exacerbate stool withholding and with time result in a lazy, baggy bowel which will require additional laxatives such as stimulants to empty. For treatment to be effective laxatives should be given daily to establish a regular bowel routine. For the same reason laxatives should not be stopped abruptly but weaned off gradually once normal bowel habits have been established1.

Top tip: Add Macrogols to age-appropriate drinks such as water, sugar-free squash, fruit juice or milk for infants and children who struggle to take the prescribed volume (infants under 6 months should not be given juice or squash). Macrogols continue to work if diluted in more water or fluid than what is recommended but not less than the specified volume.


Dietary intervention should not be used as first-line management of FC but can be useful alongside laxatives to treat and prevent the reoccurrence of constipation1.


In infants that are breastfed ensure that mum is having enough fluid, the infant is latching properly and is feeding at regular intervals. Mums should be encouraged and supported to continue breastfeeding as infants who are breastfed have softer and more frequent stools compared to infants who are formula fed3.

For formula fed babies investigate whether the formula is reconstituted correctly, and the infant is taking age-appropriate volumes. Trialling an alternative formula with different fat composition, protein hydrolysates, or lactose content may be helpful as these components have been associated with hard stools4,5. Recent studies have shown that magnesium-rich formulas can be effective in reducing stool consistency and increasing stool frequency6. Where cows milk allergy is suspected a 2-4 week trial of cows milk exclusion either through maternal exclusion or hypoallergenic formula is recommended1.


Assess fluid intake and ensure that minimum requirements are met. The below fluid recommendation is a guide and will vary depending on the size of the child, physical activity, season, and additional losses such as excessive drooling or sweating7.

Infant under 6 months: 100-190ml/kg

Infant over 6 months: 800-1000ml*

Children 1-3 years: 1100-1200ml*

Children 4-9 years: 1300ml*

Children 9-13 years: 1500-1700ml*

*will include water in food

Top tips: Having a visual reminder of how much fluid is required can be useful in toddlers and children. Fill up a water bottle or jug or have a visual chart where each cup of water can be ticked off and remember to involve nursery or school about keeping a record.


The current fibre recommendation for children over the age of two is age plus 5g/day8. A healthy diet should consist of a combination of soluble (oats, fruit, and vegetables) and insoluble fibre (whole grains, nuts, and pulses). Soluble fibre is fermented by colonic bacteria to produce short chain fatty acids. Insoluble fibre acts as a bulking agent and traps water in the digestive tract. Both types of fibre soften and enlarge stools which reduce transit times. Change to wholegrain carbohydrate foods such as cereal and bread and advise at least five portions for fruit and/or vegetables per day.

Top tip: A portion of carbohydrate, fruit or vegetables is equal to the child’s fist. Add grated vegetables to sauces or mince dishes, puree fruit to porridge oats / yogurt or introduce a daily smoothie with added fruit, vegetables, nuts, and seeds.

Pre- and probiotics

Prebiotics are present in everyday foods such as dairy products, fruit and vegetables and infant formula and is important to maintain healthy gut function. However, additional supplementation with pre- and probiotics are not recommended, as clinical studies have not shown consistent successful outcomes in treating FC2.


Establishing a healthy, regular toilet routine is essential in treating but also preventing FC. Create set opportunities during the day where the child is encouraged to sit on the toilet for 5-10 min and combine this with a fun activity such as reading a favourite book, singing songs, or listening to music. A reward chart works well to motivate younger children in addition to praise and encouragement. Keeping a stool and symptom chart is a useful tool to track progress but also provides objective information to healthcare professionals.

Daily physical activity is important for many reasons and can help stimulate peristalsis. In infants, trial gentle “bicycle” movement or pushing the knees towards to torso in a “pumping” motion.

Abdominal massage (always clockwise), a warm bath or hot water bottle can help to ease pain and discomfort and stimulate bowel movement.


Functional constipation is common in childhood and in the majority of children can be treated effectively with laxatives and lifestyle intervention. However, if constipation persists and other red flags are present such as vomiting, blood in the stool or faltering growth, consider referral to paediatric gastroenterology.


Whole nuts should not be given to children under 5 years old, due to the risk of choking.

  1. NICE (2010). Constipation in children and young people: diagnosis and management. Clinical guideline. Available at: Accessed March 2021

  2. Tabbers MM. et al. Evaluation and treatment of functional constipation in infants and children: evidence-based recommendations from ESPGHAN and NASPGHAN JPGN 2014;58: 258–274

  3. Quinlan PT. et al. The relationship between stool hardness and stool composition in breast – and formula-fed infants JPGN 1995;20:81-90

  4. UNICEF. A guide to infant formula for parents who are bottle feeding. The health professional’s guide. Available at: Accessed March 2021

  5. Vandenplas Y. et al. When should we use partially hydrolysed formulae for frequent gastrointestinal symptoms and allergy prevention? Acta Paediatr 2014;103:689-695

  6. Beninga MA and Vandenplas Y. The magnesium-rich formula for functional constipation in infants: a randomized comparator-controlled study. Pediatr Gastroenterol Hepatol Nutr 2019;22(3):270-281

  7. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). Scientific Opinion on dietary reference values for water. EFSA J 2010;8(3):1459

  8. Williams CL. et al. A new recommendation for dietary fibre in childhood. Paediatrics 1995;96:985-8


The World Health Organisation (WHO) has recommended that pregnant women and new mothers be informed on the benefits and superiority of breastfeeding – in particular the fact that it provides the best nutrition and protection from illness for babies. Mothers should be given guidance on the preparation for, and maintenance of, lactation, with special emphasis on the importance of a well-balanced diet both during pregnancy and after delivery. Unnecessary introduction of partial bottle-feeding or other foods and drinks should be discouraged since it will have a negative effect on breastfeeding. Similarly, mothers should be warned of the difficulty of reversing a decision not to breastfeed. Before advising a mother to use an infant formula, she should be advised of the social and financial implications of her decision: for example, if a baby is exclusively bottle-fed, more than one can (400 g) per week will be needed, so the family circumstances and costs should be kept in mind. Mothers should be reminded that breast milk is not only the best, but also the most economical food for babies. If a decision to use an infant formula is taken, it is important to give instructions on correct preparation methods, emphasising that unboiled water, unsterilised bottles or incorrect dilution can all lead to illness.