Modification of stool's water content in constipated infants: management with an adapted infant formula

Constipation is a common occurrence in formula-fed infants. The aim of this preliminary study was to evaluate the impact of a formula with high levels of lactose and magnesium, in compliance with the official regulations, on stool water content, as well as a parental assessment of constipation.

Thirty healthy term-born, formula-fed infants, aged 4-10 weeks, with functional constipation were included. All infants were full-term and fed standard formula. Exclusion criteria were preterm and/or low birth weight, organic constipation, being breast fed or fed a formula specially designed to treat constipation. Stool composition was measured by near-infrared reflectance analysis (NIRA) and parents answered questions about crying associated with defecation and stool consistency at baseline and after two weeks of the adapted formula.

After 2 weeks of the adapted formula, stool water content increased from 71 +/- 8.1% to 84 +/- 5.9%, (p < 0.02). There was no significant change in the stool's fat, protein or carbohydrate content. Parental impressions of constipation were improved with the decrease in stool hardness (100% with hard stools at baseline, 10% after 2 weeks), pain with defecation (90% at baseline, 10% after 2 weeks), and the requirement for rectal stimulation to achieve defecation (70% at baseline, 30% after 2 weeks, p < 0.001 for all three indicators).

This preliminary study suggests that an adapted formula with high levels of lactose and magnesium increases stool water content and improves symptoms of constipation in term-born, formula-fed infants. A larger randomized placebo-controlled trial is indicated.