You do not say how big your females are or how big the male is. Most breeders prefer to have a larger female and a smaller male.
The female that I use as a breeder is over 5lbs. I had a male, even though he was nice, he weighed in over 6lbs. I had one litter of puppies with him, but I decided against using him again because he was too large. I placed him in a pet home and purchased a smaller male. The male that I have now is under 4lbs. which is so much better in my opinion.
The problem with a larger male is the possibility of throwing larger puppies, which means a possible c-section. You have to ask if you can afford to have a c-section. If you only end up with one puppy after the procedure, most likely you will not come out ahead with that litter.
Some females are just not free-whelpers and have to have all puppies by c-section. If I have a female that requires this, after two litters, I would definitely have her spayed. It is just too hard on the mom and pups. Puts more stress on an already very small puppy.
Small, yes, the litter that I have right now ranged in size from 2.5 to
3.5 oz when they were born. Even though they grow fast and they are now approaching 1lb, it is still a very small pup and anything could happen.
Hope this answers some questions. But let us know the size of your dogs, please.