Puppy

is it true that if the dogs owner is pregnant and doesn't know it the dog can sense it

Not Likely, But There Is A Possibility That The Dog Will Sense The Babies Heartbeat Or Possibly The Heat. If The Dog Is Constantly Sniffing Your Stomach And Didn't Do It Before, It May Be Sensing The Baby. Also If The Dog Is Coming Up To You And Whining, That May Be A Sign. Usually It Is Older Dogs That Sense The Baby.

I believe so. just like animals sense death, we had a cat listed in our local paper that lived at a nursing home and who ever the cat vistied that night died during the night.
Another story tells of a dog who kept nosing at her mom's boob, finally it hurt one day to the lady went to the doctor and she found out she had breast cancer.
So yes I believe animals do tell us things.

I think they certainly notice the shift in hormones! Because dogs don't use a language to communicate, instead they understand body language and energy. So when somebody is pregnant they will have slight shifts of energy and mood and therefore their behaviour will change ever so slightly. These changes probably wouldn't be noticable to the human but animals are experts at reading body language and they will notice.

Whether or not they know weather the changes in energy are because the human is pregnant is a mystery to me though. Maybe your scent also changes when your pregnant and dogs recognise the scent???