What are Normal Defecation Patterns in Healthy Children up to Four Years of Age? A Systematic Review and Meta-Analysis.

OBJECTIVE:To summarize available data on defecation frequency and stool consistency of healthy children up to age 4 in order to estimate normal references values. STUDY DESIGN:Systematic review including cross-sectional, observational, and interventional studies published in English, that reported on defecation frequency and/or stool consistency in healthy children 0-4 years old. RESULTS:Seventy-five studies were included with 16 393 children and 40 033 measurements of defecation frequency and/or stool consistency. Based on visual inspection of defecation frequency data, a differentiation was made between two age categories: young infants (0-14 weeks old) and young children (15 weeks-4 years old). Young infants had a mean defecation frequency of 21.8 per week (95 % CI, 3.9-35.2) compared with 10.9 (CI, 5.7-16.7) in young children (P < .001). Among young infants, human milk-fed (HMF) infants had the highest mean defecation frequency per week (23.2 [CI, 8.8-38.1]), followed by formula-fed (FF) infants (13.7 [CI 5.4-23.9]), and mixed-fed (MF) infants (20.7 [CI, 7.0-30.2]). Hard stools were infrequently reported in young infants (1.5%) compared with young children (10.5%), and a reduction in the frequency of soft/watery stools was observed with higher age (27.0% in young infants compared with 6.2% in young children). HMF young infants had softer stools compared with FF young infants. CONCLUSIONS:Young infants (0-14 weeks old) have softer and more frequent stools compared with young children (15 weeks-4 years old).