I used to show dobermanns and mated my bitch only when I wanted a puppy.  I now have border collies and have worked in obedience for the last ten years.  I have a very nice two and a half year old bitch with an excellent pedigree who is working very well and I would very much like to mate her so that I can keep a puppy.  The dilema is her size, she is very small.  There is nothing wrong with her she is a very healthy young lady, bursting with energy and loves life.  Dobermanns do not vary greatly in size so it did not come into the equation, borders as you know are a different kettle of fish.  I have a nine year old dog who I worked to a high level in obedience (C only) but who I retired at the end of last year. He also has a good pedigree and I would like to use him but he is a very big dog.  I do not want to jeopardize my bitch in any way so would be grateful if any of you knowledgable people could advise me on whether the puppies would be very large  or does the size of the bitch dictate the size of the puppies.  

I certainly wouldn't use a big dog on her as there could be problems if the puppies are big.

How small is she ? bitches should be around 20" at the shoulder.

I presume both your dog & bitch have been DNA & clinically tested for eyes, TNS, CL, Hip & elbows already if you are intending to breed them together.

Is your bitch Obedience/Show/ISDS/NZ-Aust breeding ?

This is rather the same dilemma I was facing.  My bitch is the bottom of the breed standard, although in correct proportion to her height.  She is in fabulous condition, well muscled, and healthy.

A dog which I was considering using was big - bigger than the dog standard here.  We were talking a 5.5" difference.  He was the largest of his litter, where they all fell into the standard size.
My heart told me no, my head told me no.  Some old time breeders told me I was stupid for not using him if he had everything I needed.  Others who felt about their bitches like I feel about mine, told me not to chance it.
The definitive was supposed to be the vet.  He said I could use him.  He said my concern about big pups was unfounded.  That with regulating her diet and only feeding her up from about week 6 we could control the size of the pups.

I'm afraid I still said no and looked for another mate.  I couldn't chance it.

I bred Cher to a male bigger than she was.  A good 3 inches (and in my breed thats a lot!) and about double her weight.  Throughout the whole pregnancy, I was worried that she would have massive complications, especially when I saw how big her belly was getting. 

She went on to easily whelp three small pups.  Casie's pups were much bigger, and Casie was bred to a small male. 

My friend, just got a litter out of her min pin bitch.  Confirmed two big puppies (the bitch was very small, but still within breed standard, and bred to an oversized male).  She went in for a section Monday, and they came home with only one puppy.  Sadly the other puppy didnt make it. 

So there is no right or wrong, definate answer about what can happen.  No matter what decision you make, you could have to face the fact of loosing pups, or the bitch, but that can happen with any mating and pregnancy.  Cher was a easy whelper, Casie needed a section but had two pups that were a bit big, and my friends bitch needed a section and lost a pup.