What are you using for lighting? There are lots of alternatives to light maternity shots.. but if "sort of intimate" is what you want, a window light might be best.
Also, take a look at lots of maternity pics before you get started... look at how they are posed and lit... use them as a reference. My first maternity pics came out lousy cause I treated it much the same way I would a regular session.
Here is my maternity portfolio... feel free to use them as reference.. I'm sure others will post some of theirs, too.
http://jti.smugmug.com/gallery/2995645 (Warning: NSFW)