Infant constipation: the answer in three lines
A breastfed baby can go eight to fourteen days without a bowel movement without being constipated, as long as the stool is ultimately soft. Infant constipation is defined not by how far apart bowel movements are, but by their hardness, pain when passing them, and stool-withholding efforts. In 95% of cases, no illness is involved: it is what is known as functional constipation. It is linked to diet, a change in milk, the start of weaning, or, later, toilet training. Simple measures are usually sufficient; laxatives should only be given on medical advice.
This article brings together information from Assurance Maladie, pediatric gastroenterology societies, and the guidelines for academic pediatricians, updated in 2025, 2014, and 2024, respectively.
What is constipation in an infant?
Assurance Maladie provides frequency guidelines: generally at least one non-hard stool per day for infants, and at least three stools of normal consistency per week for older children. But it immediately specifies that breastfed babies are an exception. They may have only one stool every eight to fourteen days, soft and without this being constipation: breast milk is almost completely absorbed and leaves little residue.
The international criteria known as Rome IV are used by doctors for children under four years of age. They require at least two signs over one month, among the following: two or fewer stools per week; a history of voluntary stool withholding; painful or hard stools; large-diameter stools; a palpable mass of stool in the rectum.
The signs that really matter
- Hard, dry, pellet-like stools passed with straining and crying.
- A baby who stiffens, arches their back, or clenches their legs to hold in the stool.
- An alternation between hard stools and liquid stools, known as false diarrhea.
- A tight tummy, colic, and loss of appetite.
- Traces of blood on the diaper, a sign of a small fissure.
A baby who strains, turns red and grunts before passing a soft stool is not constipated. This is common before six months of age and reflects learning to coordinate straining with relaxation.
How many children are affected?
Prevalence studies report widely varying figures depending on the countries and definitions used. The reference review was published in 2014 by the European and North American societies of pediatric gastroenterology. It puts the worldwide prevalence of functional constipation in children at around 3%, with a European range of 0.7% to 12%. Two periods account for most onsets: the transition from breast milk to infant formula or the start of introducing solid foods, and toilet training. Organic causes, meaning those related to a disease, account for less than 5% of cases according to the guidelines of the Collège national des pédiatres universitaires.
Why does an infant become constipated?
In a bottle-fed baby
The main cause is formula that is too concentrated. Assurance Maladie reiterates the rule: one level scoop of powder for 30 millilitres of water, never more. Packed powder or a heaped scoop increases the protein and mineral load and hardens stools. The choice of water also matters: low-mineral water suitable for infants, as we explain in our article on bottled water for formula. Changing formula can temporarily alter stools for one to two weeks.
During the introduction of solid foods
The introduction of solid foods, between four and six completed months, changes stool consistency. A diet rich in starches and low in fruits and vegetables promotes constipation. The recommendations, detailed in our article on introducing solid foods, call for vegetables and fruit from the start, as well as regularly offering water.
During toilet training
This is the second peak. Just one painful bowel movement can be enough to create a vicious cycle: the child holds it in to avoid the pain, the retained stool hardens, and the next one hurts even more. Toilet training started too early or under pressure increases this risk. Our article on refusing the potty describes this mechanism and how to break out of it.
Rare causes that warrant an examination
Certain signs point to an organic cause: constipation present from birth, delayed passage of the first meconium beyond 48 hours, or a very distended abdomen. The same applies to vomiting, insufficient weight gain, or an abnormality in the anal region. Hirschsprung's disease, hypothyroidism, and cystic fibrosis are among them. They are rare, but it is to rule them out that any constipation in a newborn warrants a consultation.
What should you do at home, according to Assurance Maladie?
- Check how bottles are prepared: one scoop per 30 milliliters, without packing it down.
- Offer water from the start of weaning, and more in hot weather. No fruit juice or syrups.
- Add fiber from the start of weaning: green vegetables, cooked or raw fruit depending on age, and prune or pear purée.
- Massage the tummy clockwise and move the legs in a pedaling motion several times a day. The movements are described in our article on baby massage.
- Do not stimulate the anus with a thermometer, cotton swab or repeated suppositories: Assurance Maladie expressly advises against this because it maintains dependence on the action and can cause injury.
- Do not give laxatives, even over-the-counter ones, without medical advice.
- Do not reduce dairy products on your own.
For breastfed babies, Assurance Maladie advises consulting a doctor before changing anything in the diet.
After one year: positioning on the potty changes everything
As soon as the child uses a potty or the toilet, posture becomes a factor in its own right. Assurance Maladie recommends adapting the setup with a toilet seat reducer and a step stool, so that the feet rest flat and the knees are slightly higher than the hips. This position relaxes the muscle that closes the rectum and makes evacuation easier; dangling feet have the opposite effect. It also recommends inviting the child to use the toilet after meals, without insisting, and never making a failed bowel movement into a big deal. A 3-in-1 growing potty, which successively serves as a potty, a seat reducer and then a step stool, helps keep the feet in this position at every stage. Our guide on choosing a step stool explains the useful heights.
Regarding the age to begin toilet training itself, Assurance Maladie recommends between two and three years old, when the child is ready. We have detailed the signs of readiness in our article on the right age to use a potty.
When to seek medical advice, and when to call 15?
A consultation is necessary if constipation lasts several days despite the measures above, or if the child is in pain or bleeds when having a bowel movement. It is also necessary if the child soils their underwear after being toilet trained. A constipated newborn with a bloated abdomen or poor weight gain should be seen promptly, as should a child with constipation accompanied by fever or urinary problems. Emergency care, by calling 15 or 112, is warranted in the event of severe abdominal pain, persistent vomiting, or a swollen and painful abdomen.
What the doctor does
The doctor asks questions and examines the abdomen and anal area, ordering additional tests only if a disease is suspected. Treatment of functional constipation is initially based on dietary and postural measures. If medication is needed, the 2014 European and North American recommendations place macrogol as the first-line treatment, at an appropriate dose, often for several weeks. The aim is to soften the stools and break the cycle of withholding. Liquid paraffin and glycerin suppositories are second-line or supplementary options. Complications of neglected constipation, including anal fissures, encopresis, and recurrent urinary tract infections in girls, are reasons not to let it go untreated.
In summary
- Infrequent stools do not necessarily mean constipation: a breastfed baby may go up to two weeks without a bowel movement.
- What matters: hard stools, pain, stool withholding, a tight abdomen, blood.
- 95% of cases of constipation are functional; organic causes can be identified from birth.
- Properly prepared bottles, water, fiber, massage; never use anal stimulation or laxatives without medical advice.
- Once potty training begins: feet flat on a footstool, encourage sitting after meals, without pressure.
- Seek medical advice if it persists, if the child is in pain or bleeding, or from birth onward.
Sources
- Assurance Maladie, ameli.fr, “Childhood constipation” information page: recognition, things to do, consultation, and treatment, updated March 14, 2025.
- Tabbers M. M. et al., ESPGHAN and NASPGHAN, “Evaluation and Treatment of Functional Constipation in Infants and Children,” Journal of Pediatric Gastroenterology and Nutrition, 2014.
- National College of University Pediatricians, “Constipation” guidelines, item 283, online edition accessed September 15, 2026.
- StatPearls, “Pediatric Functional Constipation,” National Library of Medicine, updated January 11, 2024 (prevalence and Rome IV criteria).
