I guess you're asking both pose ideas and equipment to use. First, trying searching in this forum using "maternity" and you will find quite a few threads. However, if you want to see the ones that I shot about two months ago, you can check them out here. http://kaitcilla.smugmug.com/gallery/1541532.
I did some rearch myself before taking those shots, so some are quite similar to what you will find at others' thread. I also had some of my own.
For the equipment, it will vary significantly depending on how much you want to spend. For the shots on my site, I use 4 flashes for high key (white background) and 3 flashes for black background. It may be too much for you to start, so going with one flash is better for you. However, don't expect to get the same quality as those shots that use 3 to 4 flashes. I hope you won't get offended.
The best way to use the single flash is to bounce off of the ceiling instead of straight on shot. Make sure that the subject is at least 5 feet away from the background. For light background, you just use the room wall. For black background, use a black bed sheet or some cheap cloth and hang it on the wall. You do need some decent experience with Photoshop. Those shots on my site didn't come straight out of my camera. I had to post process individually to get those.
Good luck!