Randy Male Guppies

[Gazo]

I have 2 Guppy males in my tank - one orange and one black with orange leopard tail.
The Orange male (Randy) chases my 2 orange females - seems to prefer the more orange of the two (Flower over Tang).
The Black male (Leo) is constantly chasing my black Female (Blackie) at the moment despite her being heavily pregnant.
The other two females are Blueish and rarely get any attention from the boys.

Will the males constant flirtation with the females prevent birth?

One of the females gave birth shortly after I introduced her to the tank 5wks ago. She has shown signs of pregnancy again (currently finding spots to chill when the males are not about), but has failed to deliver - or at least we haven't spotted any fry. Can pregnancy take this long?

Also can birth never happen because I'm sure with some of the ladies their gravid spots have disappeared over night (or at least reduced in darkness).

 

[modaz]

gestation of a guppy is 4 weeks ish depending on how many fry shes holding and water conditions, the likely hood they dropped fry during the night is 100% by what you have stated. gups 95% of the time birth in twilight hours.

gups can hold on for a little while if the water is too cold or not clean enough, not saying yours is both but this is a common factor