Hungry
A baby that is hungry will not wane in their tears, because hunger just doesn’t go away. So if the cry is low pitched, repetitive, and to the same beat, it could be lunch time.
Your baby will give other signs to show you they need a milk fix as well. Rooting for the breast, putting their hand to their mouth, or trying to suck the air are all good indications that you need to get that baby some food.
This is not a cry you procrastinate with. The more they try to “drink” the air, the more gas it can cause, which will make your baby spit up or be uncomfortable.