Constipation is more common in older children, but about 10 percent of babies experience it at some point. It can happen with transitions like going from breastmilk to formula or starting solid foods. Frequency isn’t a clear indicator, as there is a wide range of normal here. Breastfed babies can pass stools only once a week and not be constipated. Other symptoms to consider: straining more than usual, a change in how the stool looks, such as small, hard pebbles, and pulling their legs up to their stomach, which is how babies react to painful cramps. Your pediatrician can suggest age-appropriate remedies.