I think Maggie also hoped that a convalescing female guppy of her's wasn't pregnant. You would hope your cobra and your Pertida (translation?) wouldn't be still pregnant after dropping over 40 fry each.

However with the ability of female guppies to carry sperm from previous matings for future batches of fry, it may be six more drops and May before you know that they are not pregnant any more.

Further more,  I have a question about whether it is good for once pregnant female guppies to be completely unpregnant. Breeders will often discard the first, suspect batch from a newly acquired female while mating her with the male of the breeder's choice. The second or third batches will be saved and watched closely since the sperm from more recent mating statistically is more likely (but not always going) to  fertilize newly ready eggs.

I wonder though if
1. it good for a female who has once dropped to not be pregnant.

2. Will she be able to get pregnant again?

3. Will an aging process kick in if the maternal hormones aren't flowing.

I don't know the answers to those questions, but zoologists will suggest that most fish will naturally reproduce until the end of their lives. (It makes sense in the competition for space, food and survival game.) When some species go sterile (annual fishes have actually been used for studies on aging), those fish "age" and decline surprisingly fast.