Symptoms that may indicate that a female Yorkshire terrier is pregnant include sluggishness, sleeping more than usual, a firmer or distended abdomen and nipples that are becoming increasingly large. Other signs that a Yorkshire terrier might be pregnant include extensive grooming and nesting behavior.
Pregnant female dogs gather things that are soft and comfortable to create a "nest" in which to give birth to their puppies. Owners of pregnant Yorkshire terriers may find the animal eats more than usual as well. Female dogs carrying puppies may also exhibit different behaviors as the pregnancy progresses and the delivery day draws near.