Just throwing this out there- my coworker recently lost her poodle mix 5 lb because her new LIve in boyfriend's dog mounted her- He is like a 20 shep mix. Well she did get pregnant and she ended up passing away! The babies were dead in her for weeks- my co worker didnt take her into the vet like I told her-    
That story goes way more in detail than what the Op was asking  but it goes to show spay and neuter your animals.. unless you are a reputable breeder-  Dont try to breed :0)     
				__________________   "People with nothing to hide don't usually feel the need to say so."         |