What are the treatment options for a 2-month-old infant with constipation?

Management of Constipation in a 2-Month-Old Infant

For a 2-month-old infant with constipation, start with small amounts (10 mL/kg body weight) of fruit juices containing sorbitol such as prune, pear, or apple juice, and if this fails, use lactulose as second-line therapy. 1

Initial Assessment

Before treating, evaluate the following key factors:

• Feeding history: Determine if the infant is breastfed or formula-fed, as breastfed infants rarely experience true constipation 2
• Recent feeding changes: Any modifications to formula or maternal diet 1
• Red flag symptoms: Look for delayed meconium passage (>48 hours after birth), failure to thrive, abdominal distension, abnormal anal position, or absent anal/cremasteric reflexes 3
• Visual perianal inspection: Check for fissures, skin tags, or redness (digital rectal exam is NOT necessary for functional constipation) 1

Treatment Algorithm by Feeding Type

For Breastfed Infants

• Continue breastfeeding on demand as the primary intervention 1, 2
• If milk protein allergy is suspected (which can mimic constipation), consider a 2-4 week maternal elimination diet restricting milk and eggs 1, 2
• Breastfed infants rarely have true constipation; normal stool patterns vary widely at this age 2

For Formula-Fed Infants

• Ensure adequate hydration and continue full-strength formula (do NOT dilute formula as this compromises nutrition without helping constipation) 1
• If cow's milk protein intolerance is suspected, trial an extensively hydrolyzed or amino acid-based formula for 2-4 weeks 1, 2
• Avoid overfeeding while ensuring adequate intake 1

First-Line Pharmacologic Treatment

Fruit juices containing sorbitol are the recommended first-line treatment for infants under 6 months:

• Prune, pear, or apple juice at 10 mL/kg body weight 1
• These juices create an osmotic load in the gastrointestinal tract due to poorly absorbed sorbitol and carbohydrate ratios 1
• Caution: Avoid excessive juice consumption as it may cause diarrhea, flatulence, abdominal pain, and poor weight gain 1

Second-Line Pharmacologic Treatment

If fruit juices fail, lactulose is the appropriate next step:

• Lactulose is authorized and effective before 6 months of age 1, 4
• Dosing for infants: 2.5 mL to 10 mL daily in divided doses 5
• If diarrhea occurs, reduce the dose immediately; if diarrhea persists, discontinue lactulose 5
• Important warning: Infants receiving lactulose may develop hyponatremia and dehydration, requiring close monitoring 5

Acute Disimpaction (If Fecal Impaction Present)

• Glycerin suppositories are an option for short-term relief and disimpaction in infants 3, 2
• This should be reserved for cases with actual impaction, not routine constipation 3

Critical Pitfalls to Avoid

• Do NOT dilute formula - this does not help constipation and compromises nutrition 1
• Do NOT rely on stool pH or reducing substances alone - clinical symptoms are more important than isolated lab findings 1
• Do NOT use dietary fiber - it is not effective for established constipation in infants 3
• Do NOT use chronic stimulant laxatives in infants 2
• Do NOT assume normal stool patterns - by 2 months, feeding patterns change to every 3-4 hours, which naturally affects stool frequency 1

When to Refer or Escalate

Refer to pediatric gastroenterology if:

• Constipation persists despite appropriate interventions 2
• Any red flag symptoms are present (failure to thrive, abdominal distension, delayed meconium passage) 3
• Bilious vomiting occurs 1

Parent Education

• Educate parents that normal bowel patterns vary widely in infants, especially between breast and formula-fed babies 1, 2
• Emphasize the importance of adequate hydration 3
• Instruct parents to monitor for warning signs and return if symptoms worsen 6