The primary symptoms of pregnancy in a Chihuahua include a hard and enlarged abdomen, lethargy, nesting and large nipples, according to WebMD. To further determine if a Chihuahua is pregnant, it is important to bring her into a veterinarian's office.
This particular dog breed can often have a difficult time during labor, so it is best to consult an expert about the possible option of a Caesarean section (C-section) during the early stages of pregnancy. A veterinarian will also be able to perform a blood test or an abdominal X-ray, which can quickly confirm if the dog has puppies growing inside of her uterus.
Additional signs your pregnant Chihuahua may exhibit include eating more than usual, and not having as much energy as she normally does. You will know when she is ready to deliver within 24 hours, because her temperature will drop below her normal temperature of 101 degrees Fahrenheit. She will also probably whine and vomit. At that point, the Chihuahua needs to go to the clinic as quickly as possible.