By 3 to 6 weeks of age, some breastfed babies have only one bowel movement a week and still are normal. This happens because breast milk leaves very little solid waste to be eliminated from the child's digestive system. Thus, infrequent stools are not a sign of constipation and should not be considered a problem as long as the stools are soft (no firmer than peanut butter), and your infant is otherwise normal, gaining weight steadily and nursing regularly.