Are there Live Plants in the tank? She could be eating Planaria, and other little yummy bugs off them. Otherwise, what are you feeding her? Does she look any thinner? When you look at her face on, does her stomach appear rounded or squarish? 
It should be noted that right before, and while giving birth female Livebearers won't eat. They have a special hormone that takes away their appetite before they start giving birth, so they won't eat their own fry.
I know you all are probably now wondering, how come everyone says parents can eat their own fry? Well, because the other Livebearers will have no problem eating them, and once the hormone wears off the female, she'll eat some too.
As far as I can tell it has been about 2 days. However, when I leave the room and come back she is sometimes swimming about, so maybe she eats so from the bottom then. When she sees me she generally hides in her stump.
Let's just attack my advice a little more...![]()
Apparently I am totally wrong, so I'll go erase it...