As your pregnant dog's belly starts enlarging, it's natural for you to wonder how many puppies she's nestling in her womb. Radiographs can confirm the number of puppies she's carrying, but not until about two weeks before her due date. Your vet uses other methods to confirm pregnancy much earlier but can't tell you the exact numbers of puppies. Canine gestation lasts approximately 63 days, but puppies can arrive a few days early or late.
Palpation
Before puppies will show up on a radiograph, your vet can confirm your dog's pregnancy via abdominal palpation. Three weeks after breeding, your vet can feel whether your dog is carrying puppies by feeling the uterus through the abdomen. The Louisiana State University School of Veterinary Medicine website describes the embryonic puppies as feeling like "walnuts." Actually determining how many fetuses are present, or whether the pregnancy is viable, is not possible through palpation. Larger dogs are more difficult to palpate than smaller ones, because the vet might have to use both hands. A two-handed method is generally less accurate. Your dog also has to cooperate. If she won't stay still or tenses up her abdomen, palpation won't work.
Ultrasound
Ultrasound is more accurate than palpation for establishing a pregnancy and can be done earlier. Your vet can show you the gestational sacs containing the fetuses by days 18 to 20, rather than waiting until at least day 21 for palpation. You'll also be able to see the fetal heartbeat if the ultrasound is performed after day 23. At that stage, however, it's still too early to predict the number of puppies. Even later in the pregnancy, ultrasound is not considered as reliable a predictor as radiography.
Radiographs
While a radiograph can confirm a pregnancy about 42 days after the breeding, when the fetal skeletons mineralize, you'll have to wait a week or more before using this methodology to determine the number of puppies. While day 50 is the earliest recommended date, Kansas-based East Central Veterinary Hospital states that waiting until at least day 55 provides the most accuracy for a puppy head count.
Preparations
Determining the number of puppies before birth is more than just a matter of curiosity. Viewing the skeletons on the radiograph helps the vet evaluate the approximate size of the puppies as well as their numbers. While most canine deliveries are uneventful, there's always the possibility of life-threatening problems for both mother and puppies. If the puppy's heads appear too large in the radiograph, your vet might consider arranging for a Cesarean section rather than risk them getting stuck in the birth canal. That's a special risk for toy dogs and brachycephalic -- short-nosed -- breeds, such as the pug and bulldog.
