Infant Constipation
Often when the baby is very young, the digestive system is not mature enough to process formula that is being used as a substitute for breast milk. This can cause constipation in the baby which can cause discomfort when passing them. Although, it is hard to say a specific time as everyone is different but one should look out for any change, dry stools or not going for 3 days.
Article on constipation and some possible causes
