Most reputable breeders retire their females at 4 to 5 years of age. Not to mention you would need to have her health tested before breeding...
There is a risk any time a female gets pregnant. Because of a yorkie's size...
a c section is always a possiblity.
I'd say...have her spayed and let her enjoy her diva status.
__________________ Deb, Reese, Reggie, Frazier, Libby, Sidney, & Bodie |