We have a 2 and 8 months old St bernard who's given birth three times already. How many times can she still get pregnant and give birth that is not dangerous to her health?

EVERY time she gets pregnant it is dangerous to her health. If you want what's best for your dog, you will stop mating her and have her spayed.

If you don't already have enough knowledge of breeding then you shouldn't be doing it. Like Akoue said, there is a risk every time and it becomes higher the more you breed from the same dog.

PLEASE stop this madness! It is not responsible to have already bred your dog three times at that age. She needs a safe, loving home with responsible owners. She should be fixed and given that, after all, hasn't she already done enough for you?

Every pregnancy exacts a terrible toll on the health and life of the dog. A female dog comes into heat twice a year making it possible to have 2 litters a year, but it is unwise and very unhealthy and unsafe for the dog to be put through such intense stress.

What you are doing is irresponsible and just down right mean.

If you had any care for your dog you would not put her through this.

Stop.

She has been pregnant three times too many already. Can you account for where EVERY single pup is from those litters at this very second?

If your dog has had that many litters in that short of a period then you have no business breeding. If you took the time, effort, and money to become a reputable breeder it would be different, but as it is you are irresponsible and abusive through your ignorance. The term for you is a Backyard Breeder, and that's no compliment.

Why haven't you had your dog spayed by now? This is lunacy.