I'm not currently pregnant... but I have been... and I currently have a big enough belly that it could be construed that way...

I am very comfy at my desk. I am actually sitting on a broken computer chair... I am very heavy and a few of the wheels snapped off so I removed the rest. I essentially am just balancing on the centre post now. I never use the backrest. It is at a good height for me as well. As I lean up against desk, my breastbone presses up against the edge. My legs are kind of out in front of me. I frequently will stand and stretch. It is nice.

http://i.imgur.com/1D2ISw0.jpg