The variation in stool patterns from 1 to 42 months: a population-based observational study

Objective: To document the normal stool patterns of young children. Design: Prospective population-based longitudinal study. Setting: Avon Longitudinal Study of Parents and Children (ALSPAC). Subjects: 12 984 children, whose parents completed questionnaires at 4 weeks, 6, 18, 30 and 42 months on their frequency of bowel movements and the consistency and colour of their stools. Results: Stool frequency declined from a mean of 3.0 times/day (3rd centile 0.6, 97th centile 5.9) at 4 weeks to 1.3 times/day (0.6, 2.7) at 42 months. Stool consistency was soft in most babies with nearly half passing liquid or curdy stool at 4 weeks. 14% of babies usually passed a hard stool at 4 weeks, rising to 30% at 42 months. Stool colour was commonly yellow at 4 weeks and had changed to brown by 6 months. Black stools were extremely unusual at all ages. Conclusions: These data on the changes with age in the stool patterns of young children will be useful for clinicians.