Chihuahuas are a brachycephalic breed of dog, which means they have flatter faces and smaller litter sizes compared to other breeds. On average, Chihuahuas have around 3 puppies per litter, but older Chihuahuas can have larger litters with up to 5 or 6 puppies. Chihuahuas usually have smaller litters when having puppies for the first time. Chihuahuas are more likely to have health complications if they have larger litters. In 2018, a Chihuahua in Kansas gave birth to a world record litter of 11 puppies. C-sections are often necessary for Chihuahuas to safely give birth due to their narrow hips and larger head sizes of puppies.

Responsible breeders limit Chihuahuas to no more than 4 litters in their lifetime. Other brachycephalic breeds include French Bulldogs, Pugs, and Shih Tzus. Chihuahuas should only have 1 litter per year and should only get pregnant every other year to allow their bodies time to recover. Chihuahuas are pregnant for an average of 63 days, and an ultrasound or x-ray can determine the number of puppies in a litter.