Can Puppies Be Missed In An Ultrasound?

Your dog is pregnant?! Congratulations!

It’s an exciting but nerve wracking time having puppies on the way. We’re here to talk you through all the questions you might have, from using hormone, ultrasound and x-ray tests to confirm your pup’s pregnancy, to how to work out how many puppies she’s expecting.

Can Puppies Be Missed In An Ultrasound?

Ultrasounds are used for estimating litter size but aren’t considered accurate as puppies can be easily missed. When used with other forms of analysis, such as x-rays, they can provide a more accurate guess and they can also provide important information about the health of the puppies.

How Far Along The Pregnancy Can You See A Puppy On Ultrasound?

By the third week of pregnancy it’s possible to detect the tiny forms of growing foetuses, and even their heart rates, using an ultrasound. At this stage they only appear as little lumps.

It’s advisable to wait until at least day 25 or even 28 before getting your pup scanned, as very early pregnancies can be reabsorbed into the mother’s uterus. By leaving more time for the pups to grow, the benefits of a later scan is being able to see the pups in more detail.

Why Are Puppies Not Showing On Ultrasound [False Negative]?

Ultrasounds are not always completely accurate, here are a couple of reasons why you might encounter some surprise puppies in your litter.

They’re hiding!

Ultrasound is a great method to create an image of what’s going on inside your pregnant pup, but it can’t see around or behind the objects it’s viewing.

“Camera shy” puppies might be able to avoid detection after multiple scans and leave you with an unexpected addition to the family!

Their heart rate wasn’t detected

With large litters of puppies, there’s a lot of confusion going on and it can be hard to separate one heart beat from another. It’s possible that in the commotion of all the other heartbeats, theirs was missed.

You can’t get a clear image

Ultrasounds work by firing a narrow ray of ultrasonic beams into your dog’s womb and create an image by reading the “echoes” that are reflected.

If your pup is too full of nerves, to sit still during the procedure, it will be hard to get a clear reading of how many puppies she’s got.

It’s too early for an ultrasound

If your ultrasound is showing a false negative pregnancy, i.e. no pups, even though you know that she’s pregnant, it’s probably because they’re still too small to be seen on an ultrasound! Try again later after about a week, making sure she’s at least day 25 of her pregnancy.

Can Puppies Hide In The Rib Cage And Now Shown On Ultrasound?

In the first stages of pregnancy, your dog’s womb is higher up in her abdomen, under her ribs. This means that any puppies hiding in there might be missed by an ultrasound.

By day 40, the puppies have usually dropped into the womb.

At this stage in her pregnancy, your pup’s belly will visibly start getting bigger as her womb drops lower into her abdomen, preparing for the later stages of her pregnancy as the puppies develop.

What Will An Ultrasound Show In A Dog?

Ultrasounds form a real-time picture of tissues, muscles and organs. However they’re not so good at imaging non-fluid substances, such as bones and air in the lungs.

This means that ultrasounds can provide an image of the puppies growing inside your dog’s womb, or her spleen or her liver depending on what your vet needs to see.

Is It Safe To Ultrasound Scan A Pregnant Dog?

Yes, ultrasound scans work by recording the reflection of ultrasonic waves. These sound waves are considered safe, as they don’t use ionising radiation, like x-rays do. They are still incredibly powerful and can be used therapeutically to heat up tissues, but in the hands of an experienced veterinarian your pup is perfectly safe.

How Accurate Are Ultrasounds For Detecting Puppies In A Pregnant Dog?

As we’ve discussed, ultrasounds can provide an estimate for the number of puppies your dog is carrying but they’re not viewed as very accurate. An x-ray at around day 54 could provide a better estimate.

When Is The Best Time To Ultrasound A Pregnant Dog 21, 28, 30 Days?

At 21 days it’s hard to get an accurate ultrasound result as it’s probably too early to hear the heartbeat of the unborn puppies and their forms are still so hard to distinguish.

By day 28 and 30 you should be able to hear the puppies’ heartbeats and make an estimate of the size of the litter. This is when most vets would recommend a scan.

Can Puppies Be Missed On Ultrasound At 21, 28, 30 Days?

Puppies can always be missed on an ultrasound, but it’s especially easy at day 21, when the growing gestational sacs are still hard to distinguish and count.

Days 28 and 30 should be perfect for a scan, but don’t leave it too long!

The bigger the puppies and your dog’s belly grow, the harder it is to get a clear puppy count!

What Is The Best Time For A Pregnant Dog To Get An Ultrasound Scan?

It’s usually recommended by vets to get an ultrasound on the 4th week of the pregnancy (day 25 onwards). An ultrasound should confirm or deny a pregnancy and can give an estimate about the litter size, but they’re not always accurate!

It’s best to confirm your dog’s pregnancy before getting a scan, through a blood test or manual palpitation (feel by hand) from your vet, as an ultrasound can be a costly investment.

Where Can An Get An Ultrasound Scan For My Pregnant Dog?

You should easily be able to arrange an ultrasound appointment by calling your regular vet.

Ultrasound technology has so many applications that it would be hard to find a practice without one!

Why Is There Only One Puppy On Ultrasound?

There are a number of reasons why your dog might have a one pup litter. Small and miniature dog breeds are usually disposed to having a smaller, or singleton, litter. With less space to share inside mum’s tum, it makes sense.

Older dogs have an increased chance of having a one puppy litter, especially after the age of 7 years old.

You might even have some other pups staying undetected during the scan. Keep your eyes peeled during future scans for surprise arrivals!

What Does It Mean When A Dog Has A Singleton?

When a litter contains only one puppy, this is known as a singleton.

Surprising, singleton births can seriously complicate pregnancies.

Just one puppy can’t generate enough hormones to activate labour, or even milk production. This means that a singleton often grows too large for a normal pregnancy and C-sections are very common to ensure a safe labour.

This can lead to complications after the birth too, such as bottle feeding, if your mumma pup doesn’t have enough milk.

Can A Puppy Scan Be Wrong?

There are many reasons why you might receive conflicting scan results. If you’ve already scanned your pregnant dog and her litter appears smaller on the second count, it’s possible that neither scan is wrong. Instead, the growing embryos might just have been reabsorbed by the uterus.

Scans are great at providing information about the health of the litter, their heart rate information and an estimation on the number of pups. However, they can be misinterpreted and aren’t 100% accurate.

Can Ultrasound On Dogs Be Wrong?

Ultrasounds may provide false information about the size of the litter if puppies are hidden or the image is misinterpreted. Early ultrasounds might also confirm a pregnancy which never becomes full-term.

Ultrasounds can never really be wrong, but they can definitely be misinterpreted.

Can Ultrasound Show How Many Puppies?

Ultrasound can create an image of what’s going on inside mama’s tummy. You should be able to see the growing forms of the puppies and listen to their heartbeats.

Through visual and aural analysis of this information, your vet should be able to estimate how many puppies there are.

It’s not considered an accurate method to determine litter size though, as there are many reasons why puppies could be miss counted.

What Causes False Pregnancy In Dogs?

Sometimes dogs will go through all the symptoms of pregnancy including swollen nipples and behavioural changes (becoming more maternal or aggressive) without actually carrying puppies.

This is caused by normal changes in hormone levels about 42 – 56 days after they’ve been in heat. As their levels of progesterone start to drop and their levels of prolactin increase, this tricks your pup’s body into thinking it’s pregnant.

What’s The Longest A Dog Can Be Pregnant?

A dog usually goes into labour on their 9th week of pregnancy, around day 60-63.

Some factors may influence how long your pup will be carrying her babies, such as her age, breed and the size of her litter.

Is An Ultrasound More Expensive Than An X-Ray [Cost Comparison]?

YES. Ultrasounds will cost you around $300-500 dollars, whereas an x-ray will usually only set you back $150.

These prices can fluctuate though, based on factors such as location, veterinary practice and whether this is covered by your insurance.

Is An Ultrasound More Reliable Than An X-ray [Can It Miss Puppies]?

As we’ve discussed, although they have plenty of benefits, ultrasounds are notoriously inaccurate when it comes to counting puppies.

No diagnostic tool can be perfect though and it’s possible to miss puppies on x-rays too, if the scan was taken too early for the puppies’ bones to develop. The results could also be misinterpreted by the vet, it’s hard to work out the exact number of puppies when you can only count a mess of bones!

When Can You See Puppies On An X-ray?

By around day 42 of pregnancy, the foetuses begin to develop their bones through a process known as ossification. At this point, you can have an x-ray done, to get a more accurate estimate for the number of puppies and work out how they’re growing.

When To X-Ray A Pregnant Dog?

It’s around this time (week 6 of pregnancy), that it’s best to x-ray your pregnant pooch. X-rays are powerful diagnostic tools and can give you some clues about the health of the puppies, including whether or not a C-section might be necessary.

Is It Safe To X-Ray A Pregnant Dog?

X-rays use powerful ionizing radiation to form a picture of what’s going on inside the body.

Although this form of radiation can be damaging, when used in moderation and in the hands of an experienced vet, your pup is perfectly safe.

What Is More Accurate An Xray Or An Ultrasound?

When it comes to estimating the size of a litter, x-rays are generally considered the best option.

This is because skeletons are reasonably easy to count in a fixed image. Miscounts still happen though!

Although ultrasounds are less accurate at litter estimation, they can be implemented much earlier than x-rays to confirm or deny a pregnancy. They are also incredibly important at assessing the health of the pups through measuring their heart rates.

Can A Blood Test Detect Pregnancy?

Your dog can have a blood test for the presence of the hormone relaxin as early as day 22 of her pregnancy, although you’re advised to wait a little longer. This hormone is released by the placenta, in response to the implantation of an embryo, and remains present throughout the pregnancy.

What Is A Relaxin Rapid Test?

A Relaxin rapid test uses enzyme lateral flow, just like a human pregnancy test, to give a positive/negative result in just 10-30 minutes, by analysing plasma in blood samples.

How Early Can A Relaxin Rapid Test Detect Pregnancy?

A Relaxin Rapid Test can detect pregnancy as early as day 24 of pregnancy. By day 26, it is considered a more accurate test for exclusion of pregnancy.

How Reliable Is Relaxin Rapid Test?

Relaxin Rapid tests are not considered 100% accurate and can provide false negative pregnancy results, especially when taken too early. They may also provide false positives.

It’s advised to take 2-3 tests, with weekly intervals, if there is any doubt in the result.

Is My Dog Definitely Not Pregnant If The Relaxin Rapid Test Gave A Negative Result?

The relaxin test is notorious for sometimes giving a false negative result. This may be the case if the test was taken too early for there to be sufficient levels of the hormone relaxin present.

It’s best to repeat the test after a week, to be sure of the negative result. If symptoms of pseudopregnancy continue to occur with a negative test, you might be advised to take a third test after more time has passed, or undergo further diagnosis.

Is My Dog Definitely Pregnant If The Relaxin Rapid Test Gave A Positive Result?

No, a positive relaxin result doesn’t always mean your dog is going to have puppies.

A false positive result may occur due to an error in the lab.

Alternatively, your pup might have received a correct positive prognosis, but the pregnancy has been terminated. It’s fairly common for developing embryos to be reabsorbed and a later relaxin test can confirm with a negative result.

Are All Puppies To Be Born Alive And Well If The Relaxin Rapid Test Gave A Positive Result?

Relaxin tests can only confirm or deny the presence of the pregnancy hormone, relaxin.

Your vet will give you all the help and advice you need to look after your pregnant pup, including any further tests if they’ve got concerns.

After about a week you can get your first ultrasound, to get a peak of the pups and hear their hearts beating.

What Are The Other Ways Of Finding Out My Dog Is Pregnant?

Besides getting a relaxin test, ultrasound or x-ray, there are a couple of other ways to work out if your dog is pregnant.

Manual Palpitation

This just means feeling your dog’s tummy from the outside. An experienced vet could determine the presence of puppies as early as 22 days into the pregnancy.

Behavioural changes

If your pup has started eating less, sleeping more and is getting enlarged nipples, these are all tell-tale signs that she might be pregnant.

Of course, don’t start celebrating too early because pseudo pregnancies can occur as well. Keep your eyes out for weight changes and maternal behaviour, such as stealing your cuddly toys to use as her puppies!

References

1. False Pregnancy in Dogs: Symptoms, Causes, Treatment, and FAQs | PetMD
2. Canine Pseudopregnancy | Animal Health Topics / School of Veterinary Medicine (ucdavis.edu)
3. Ultrasound (nih.gov)