Aside from the information that you've already given her, it's not healthier for her to have a litter of puppies. Pregnancy and whelping come with some huge risks. Is she prepared to lose her dog in the process?
Also, each heat cycle she goes through puts her at an increased risk for uterine and mammary cancers. The longer she goes without being spayed, the more likely her risk of deadly uterine infections.
Its much safer and healthier for her to be SPAYED, before she has a litter.
Then, there's the whole other aspect of her dog even being the quality to breed. Chances are, she has no idea what the background is. Anybody that has a dog for breeding should be doing extensive research into their background to know what that particular dog is capable of reproducing. The good, the bad (and the ugly!
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