Hi Wednesday13 - I have to disagree with a lot of this. I have very rarely removed males from pregnant females and have never once had a 'premature' birth or had a single still born pup from 100 + pups born. To say that keeping males with pregnant females will almost always cause premature birthing of pups is certainly an overreaching statement. An over zealous male that continues to try and mate an already pregnant female certainly carries that risk. It has been my experience that most males will cease to go after pregnant females, I would assume the holding female gives off a hormone or similar into the water that alerts males that she is not in a position to be mated. i am sure in some cases that cue may be ignored by an immature or overly keen male, especially in the confined of a glass cage.
Do you have any reference to females absorbing pups? I have never witnessed this in the past and I don't know of any animal capable of reabsorbing a fertilized and developing embryo - once a pregnancy is confirmed through movement I have never seen a female 'reaborb' pups. They can certainly reabsorb follicles prior to fertilization. This has also been observed in many reptiles, particularly snakes.