I did a maternity set a little while back and got some good ideas from here - http://www.momphoto.com/

I used a simple backdrop of one white and one black purchased from the local Hobby Lobby craft store. It was 2 yards wide by 4 long. If you happen to clip off the sides and have some wall showing, you can always photoshop. I prefer to focus on the tummy rather than backdrops and props.

As for your photos, I do like the profile shots. The first one, as suggested, I would move her away from the wall to stop the shadow. Get some of her lying on the floor, sitting with hands on her tummy. Have her husband sit behind her and both hold her tummy. Take a photo looking down from her head at her tummy (helps her remember what it looked like . ) I think your lighting is fine, just get creative with what your ideas, but remember that mommy will tire out easily from getting up and down so try to do all the shots on the floor at once.