If it’s the first time, call me. If you refused, because " busy today / school tomorrow / cat is giving birth / hair is not done, etc. ", you should not call. These "causes" usually do not disappear!
Yyy: Well not always, if once this is - maybe, the cat is really giving birth :) But if the cat gives birth every two days, then, of course, it is not worth naming.
Zzz: If the cat is giving birth at all, it should be careful