one of my aquarist friends had 1 male guppy and 2 female guppies. 1 female guppy died yesterday after giving birth, RIP :'(. is there any partiular reason or it happens sometime?
Sometimes the female is weak after birth and the male aggravates them really bad. Are there lots of plants(real or artificial) in the tank for fry and females to hide/rest in? If not this might help in the future.
She may have been overstressed with giving birth. Maybe next time if you have a smaller quarantine tank, move her to that tank so she can give birth without the males picking on her. See if that helps. Otherwise lots of hiding places.
That is so common these days.....
I've even heard of the fry getting stuck in the female, and she can't squeeze them out and she and the fry die. It's sad but true.