If the females look so big they're about to pop, and they kinda bounce along the bottom of the tank you can probably expect babies within that week. But there really is no "labor sign" that I'm aware of, but I'm don't pay attention to guppy breeding enough to know. Alls I know is one day I have fat females, the next day I have babies in the tanks, which then become food for my small mouthed predators.
~~Colesea
