dog pregnancy

Question
Have you ever seen a dog not look pregnant or gain weight with first litter at Day 44?  She is right at 4 pounds so very small.  Stud was 3 pounds. Vet said not pregnant by sight until he palpated and changed to "definitely two, maybe 3" at Day 40.  Planning an xray at Day 55.  Picking up very very faint doppler heartbeat sound, but only in the 130 range.  Could the vet have been feeling feces or something else?
Thank you.

Answer
I have seen a standard poodle that was so thin that its ribs were showing and the next morning gave birth to nine puppies.  With her, they were all in the rib cage.  And I have seen bitches so fat that you would swear that they must be carrying ten puppies and have nothing.  I know you don't want to hear this, but you will have to wait for the X-rays.  I know how hard that is because I have been in your position so many times and unfortunately it is the same every litter unless you can sit and actually see the pups move.  The good news is that you only have to wait two more weeks and then you can see the Xray.
nancy
PS so sorry I couldn't tell you more.  Stop worrying it makes the mom nervous.