Something to say..
Babies cry to communicate.
It may be a need - i'm hungry, cold, wet, gassy. Or it may be to get your attention, especially as they begin to realize there are people who love and hug them when they "communicate" with an attention getting cry. It's their way of sending you a signal, because they haven't mastered the phrase "change my diaper
, it's full of poo" or "mommy i love you and i need a hug".