Puppies or no puppies -Ultrasound Wrong?

Question
Dear Renee,

We had 3 well timed (prog.tests) & AI's w/our Female Bulldog.  Last Breed on 12/7.  We did an ultrasound at 28 days and vet said he wasn't sure.  come back in 10 days.  We did, saw another vet - he said no puppies.  Is it possible at 38days after last breed to not see pups?

Thanks

Answer
Hi Wendy. I wouldn't give up yet. Have an x-ray done at 50 days. I like the x-rays much more than the ultrasound. I have known of dogs who showed up not pregnant on the ultrasound, and still whelped a litter. If the x-rays show no puppies, then I would start to try to figure out what went wrong. If you decide to have the x-rays done, please let me know what they show.