What is the best approach to manage constipation in a 5-month-old infant?

Management of Constipation in a 5-Month-Old Infant

For a 5-month-old infant with constipation, first-line treatment consists of fruit juices containing sorbitol (prune, pear, or apple juice) at 10 mL/kg body weight, followed by lactulose if juices are ineffective. 1

Initial Assessment

Before initiating treatment, evaluate the following key elements:

• Feeding history: Document whether the infant is breastfed or formula-fed, feeding frequency, and any recent changes in feeding patterns 1
• Growth parameters: Poor weight gain or growth concerns warrant further evaluation for organic causes 1
• Red flag symptoms: Look specifically for bilious vomiting, which indicates potential underlying pathology requiring immediate attention 1
• Perianal inspection: Visually inspect for fissures, skin tags, or redness—digital rectal examination is typically unnecessary for functional constipation in infants 1

First-Line Dietary Interventions

Breastfed infants: Continue nursing on demand without interruption, as breastfeeding should never be discontinued in favor of formula feeding for constipation management 1, 2

Formula-fed infants:

• Maintain full-strength formula—do not dilute, as this compromises nutrition without helping constipation 1
• Introduce small amounts (10 mL/kg body weight) of sorbitol-containing fruit juices (prune, pear, or apple juice) to increase stool water content and frequency 1
• The North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition specifically endorses these juices because their poorly absorbed sorbitol and carbohydrate ratios create an osmotic load in the gastrointestinal tract 1

Pharmacologic Treatment When Dietary Measures Fail

Lactulose is the recommended next step if fruit juices are insufficient 1:

• For infants, the initial daily oral dose is 2.5 mL to 10 mL in divided doses 3
• The goal is to produce 2-3 soft stools daily 3
• If diarrhea occurs, reduce the dose immediately; if diarrhea persists, discontinue lactulose 3
• Improvement may occur within 24 hours but can take 48 hours or longer 3

Special Considerations for Milk Protein Allergy

If constipation symptoms persist despite standard management, consider milk protein allergy, which can mimic constipation:

• Evaluate for signs of milk protein allergy in the feeding history 1
• For breastfed infants: Consider a 2-4 week maternal exclusion diet restricting at least milk and egg 1
• For formula-fed infants: Consider changing to an extensively hydrolyzed or amino acid-based formula 1

Critical Warnings and Pitfalls

Avoid excessive juice consumption: While fruit juices are first-line therapy, excessive amounts can lead to diarrhea, flatulence, abdominal pain, and poor weight gain 1

Do not use bisacodyl: There is no safety or efficacy data for bisacodyl use in infants under 6 months, and safer alternatives exist specifically for this age group 4

Monitor for warning signs: Instruct parents to return if symptoms worsen, including development of vomiting, refusal to feed, or signs of distress 1

Avoid overfeeding: Small feeding adjustments may help—ensure adequate intake without overfeeding 1

Parent Education

Educate parents that normal bowel patterns vary widely in infants:

• Newborns typically have bowel movements after most feedings 1
• By 2 months, feeding patterns change to every 3-4 hours, which naturally affects stool frequency 1
• Many cases of perceived constipation are actually normal variations in infant bowel patterns and do not require treatment 2