Can animals sense if you're pregnant?

Ok, I keep researching and researching, if its a known fact that animals can sense if you are preg. My one cat that I have acts totally different around me now, he is more loving than usual, and he just downright will not kleave my side... Whats your...

opinion on this? Only good reasonable answers please.

I'm pregnant too, and I spend a lot of time at my grandmothers. Combined, we have a lot of pets, and they each treat me differently. Two are more affectionate, my dog is more playful and listens better, one indifferent, and their 15 yr old male dog just acts the same. They all want to stay in my room when I leave though. My sister's boyfriends dog even walked with me to the convenient store about two blocks from her house, whining and checking out everything in the sidewalk. He even stopped at a crack in the sidewalk, made sure I got around it safely(nudged me away from it, LOL), and waited right outside the door to walk me back. LOL.
In my opinion, I think they do know. I mean, your personality changes, as well as the way you take care of yourself. Most anyone who spends everyday with you could pick it up, why not an animal who is more perceptive on a completely different level from a person?

Thanks for the answer, I think it is awesome that animals CAN tell... Well some of them at least! Anywho, it kind of wierds me out when my alarm goes off for me to wake up, because he'll come running, and start meowing at me... Then he'll jump on top of me untill I start to pet him... Its cute I guess, but with all the preg. hormones, sometimes it just pisses me off.. LOL