what is ultrasound?
'Ultrasound' is ultra-high-frequency sound waves, way beyond what humans and animals can hear.
The probe of the scanning machine transmits these sound waves into the body and the onboard computer uses the echoes
that bounce back to create black and white images of organs and structures inside.
The probe is moved around the bitch's belly in a set sequence to get views from different angles. The image on the screen is updated
many times a second, so the scan can show movement as well as shapes. A late-pregnancy scan can show a puppy's heart beating, sometimes moving
a paw or even opening it's mouth. Because it uses sound waves and not X-rays (radiation), ultrasound is harmless when used by a trained technician.
what does a scan involve?
The bitch stands on a flat surface (the floor for most dogs, or a big table for toy breeds like Chihuahuas, Yorkies, etc) and a water-based gel is applied to the belly so that the probe can make good contact with the skin. Good ultrasound images are possible from smooth-coated dogs with very little fur on their bellies, but to get a satisfactory image from double-coated or long-coated breeds it may be necessary to shave a small strip of fur on the tummy between the lower nipples so that the probe can actually touch the skin without fur getting in the way. Ultrasound waves can't travel through air and because a dog's fur traps air pockets in it, this can really downgrade the quality of image.I'll tell you if I think a trim would help, and you can decide whether or not you want this to be done. Some dogs are happier if their owners do a trim ahead of the scan. There is only a small area that needs clipping, shown by the purple area in the picture below. It's a maximum 8cm by 20cm on a big dog, much smaller on a toy breed. This trim is discreet and shouldn't show on a bitch when she stands up. It doesn't have to be complicated - a scissor trim is fine!
where does the scan take place?
The ultrasound scanner is completely portable, so scans can be carried out wherever there is access to electricity. Scans are best performed in a calm, quiet room where the bitch can settle, away from distractions such as other dogs or young children. The bitch's favourite person helps to hold her front end steady (treats can help!) whilst the operator works at her back end. Unlike a clinic appointment where the bitch might be taken away and returned ten minutes later with a verdict, you stay with your girl the whole time and get to see the scan taking place. Friends and family are welcome to watch the scan being done too, provided they can stay quietly in the background and this isn't too distracting for the bitch.Please note that I really, REALLY don't like being video'd while I'm working, neither do I appreciate the scan being live-cast to social media! I understand your excitement, but please respect my privacy as much as I respect yours. Images from the scan will be emailed to you afterwards and you are welcome to use those as you wish.
does ultrasound hurt?
No! Ultrasound scans are non-invasive (meaning all the equipment stays outside the bitch) totally painless and absolutely safe in the hands of a properly trained operative. The scan itself takes around 10-20 minutes, depending on how settled the bitch is and what information the client needs to know. Allow around 30 minutes for the whole appointment as it takes a few minutes to get to know your bitch and set the equipment up. An ultrasound scan should not be an unpleasant experience for your bitch; a scan in the comfort and security of her home is ideal if she gets anxious about car rides or trips to the Vet.
when is the best time to scan?
In dogs an ultrasound scan can accurately confirm pregnancy from 28 days of gestation. The problem is that's an impossible date to pinpoint. Even if you know the date your girl ovulated and you know the date(s) she was mated, nobody can know the date the eggs were actually fertilised and gestation began. Healthy sperm can survive inside the female for up to 7 days so if she ovulated late it could be that fertilisation happened up to a week after mating. The rule of thumb then, is that the best scan results are achieved between 30 - 35 days after the last mating.So once your bitch has been mated for the final time, get in touch to arrange your scan appointment for at least 30 days (one calendar month) after the last mating. With that much notice I can usually arrange a time and date to suit you.
Resist the temptation to have your girl scanned any earlier than this, after all you could be a week ahead of yourself! Before 30 days the gestational sacs can be very small and difficult to see. Trying to find them at such an early stage is frustrating, time-consuming, and could even be unsettling for the bitch. Embryos grow surprisingly fast so waiting a just a few more days can literally make all the difference to obtaining a straightforward, positive scan.
why wait 'til after day 30 to scan?
images from Cornell University, College of Veterinary Medicine.
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day 27
We need a certain amount of tissue 'mass' to bounce the ultrasound waves off - and this tiny embryo is only about the size of a big grain of rice.
However, embryos grow at an incredible rate ... -
day 31
... after all they've got just 63 days to go from a ball of cells to a fully formed puppy. Four days later the embryo is around 10-15mm long, so there's more mass for the ultrasound waves to reflect off.
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day 34
Just one week later the embryo is approx 15-20mm, about the size of your thumb nail. There's much more to see and every chance of a straightforward diagnostic scan.
estimating litter size
The sole point of a scan is to determine whether or not a bitch is pregnant. Trying to count puppies and come up with an accurate number, is NOT a good idea. No matter how thorough or careful the scan, all you can see is what is there on that day. It is completely normal for more or less pups to be born than are counted at a scan. This isn't the fault of the machine or the operator, it's simply mother nature at work.if fewer pups are born than expected:
- Puppy skeletons start to form around day 35 of gestation. Earlier than this it is surprisingly common for foetuses to fail to thrive and to then to be completely absorbed by the bitch, leaving no sign that they ever existed. (BSAVA estimate normal absorption rates at 5 -11%.) A scan before 35 days may show foetuses that the bitch later absorbs.
- Bitches absorb pups (sometimes, sadly, an entire litter) for many different reasons. She could have hormonal or physical reasons that she cannot maintain a pregnancy, she may be unwell or stressed. There could be a problem with the foetuses themselves. Some breeds are simply more prone to absorb than others. Always consult with your vet to rule out any underlying medical issue that could be causing the problem.
- A foetus cannot be regarded as 'viable' unless a heartbeat can be seen on the scan. Even then, there is no guarantee that it will survive through to the end of the pregnancy.
if more pups are born than expected:
- Bitches can quite often carry one, two or even more pups tucked up high under the ribs, beyond the normal scanning parameters. Again, some breeds are more prone to this than others.
- You succumbed to temptation and you called the scanner in too soon. Foetuses grow very quickly and before day 28-30 they are extremely small (think grain of rice) and difficult to find. A scan may spot just one or two when actually there's several more tucked away, undetected.
- After about day 35 the pups have grown to a size where they start to overlap each other on the scan - and telling one pup from another becomes increasingly difficult. Any one pup may end up being counted twice, or not at all.
You are of course, welcome to draw your own conclusions about numbers, from the scan images!
do you scan other animals?
No, I only scan dogs.Small mammals like rabbits or guinea-pigs find the process stressful. Cats in particular do not enjoy being smeared with gel and are well armed to express their outrage.
Scanning small livestock like goats or sheep requires a tough wrist-mounted machine designed for farm and outdoor conditions. Scanning horses or cows is done internally; this makes it an 'invasive' procedure which is illegal for anyone other than a vet or DEFRA licensee to do.
I absolutely do not scan humans. That is the job (and privilege) of professional sonographers in hospitals.
can I come to your house for the scan?
No. I am a mobile scanner. I am not insured to scan clients at home.I look forward to meeting you and your girl soon.
