Career Change While Pregnant- bad move?

I currently have a good job that pays well, but I’m miserable in it. I’ve been here about a year and half and I’m not sure I can take it a whole lot longer. My boss thinks I’m doing a great job, but I can’t stand working with him. It’s not using my best skills and I’m beyond burnt out with the job and the people (all two of them). I’ve begun searching for other job opportunities, but I’m a little scared of jumping ship while I’m expecting. Has anyone changed career while expecting? What was it like? How did you tell your new employer you were expecting?

Part of me thinks I should just stay out until after the baby arrives (in May) and another part of me can’t imagine staying here that long.