What Can Ultrasound Detect in Pregnant Dogs?

Canine pregnancy lasts between 57 and 72 days.
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Whether Lady's pregnancy was planned or not, it's wise to confirm her upcoming blessed event. You can't run to the drugstore to pick up a pregnancy test for her, but the vet can confirm her condition. He uses several methods to confirm your pup's condition, including palpation, ultrasounds, hormone testing and radiographs.

Ultrasound Technology

An ultrasound is a safe, non-invasive method to look at your pup's internal body structure. During an ultrasound exam, high-frequency sound waves are directed to a specific area -- in your dog's case, her abdomen -- where they're transmitted through, reflected or absorbed by the tissues they encounter. The reflected waves return to the probe as an echo and are converted to an image, resulting in a two-dimensional picture of the area being examined. It's useful for more than pregnancy; ultrasound technology helps evaluate heart conditions and diagnose cysts and tumors.

Ultrasound to Confirm Pregnancy

If Lady's pregnancy is planned, ultrasound can sometimes confirm her condition as early as three weeks after breeding; however, it's not always conclusive that early. Generally, you can get a reliable ultrasound diagnosis 28 days after she mates. It's particularly valuable between days 33 and 45 of pregnancy, when it's too late to palpate a dog and too early for x-rays.

X-Rays for Litter Size

If you're curious about how many puppies to expect, ultrasound isn't the best option. Because of the way puppies are positioned in the abdomen, it's difficult to accurately count the number of puppies in an ultrasound; puppies may be counted more than once. An abdominal x-ray during the last two weeks of pregnancy is the most dependable method to determine the size of Lady's litter.

Ultrasound for Viability

Though ultrasound won't tell you how many puppies to expect, it does have value beyond confirming pregnancy. The information gained from the fetal heart rate can give an indication about fetal viability. The normal heart rate for a canine fetus is 200 beats per minute. If the ultrasound picks up an increase or decrease in the heart rate, it's indicating fetal stress. If there's no heartbeat, it indicates fetal death.

Other Pregnancy Diagnosis Options

If Lady cooperates, the vet may be able to confirm her pregnancy about four weeks in by abdominal palpation. Palpation requires a skilled hand and relaxed dog to accurately confirm pregnancy by touch. Radiographic x-rays can confirm pregnancy, and if you can wait until the eighth week of pregnancy, they'll provide you with a puppy count. A hormone test, Relaxin, can diagnose pregnancy as early as the 21st day after breeding, but false negative results can occur. If Lady has a hormone test with a negative result, she'll likely require an additional test to confirm the results in seven to 10 days.