it can be but if your comfterble then i cant see there being a problem. but i do suggest asking a doctor or youmidwife/gyny and congrats and good luck..
no. as long as you are not to big but it will become uncomfy then. try a body pillow between your knees and under your belly. I just got one a few weeks ago and love it!!! It was 8.50 at target :) my kind of price!! but as with anything else if you are concerned ask your dr