In my mind, there are few things more beautiful than a pregnant woman. This is a very special time and a memory really worth saving, especially when you consider how much these photos will mean to the child you are carrying, later in life. You can be photographed alone, or with your partner and/or your children.
Please don't assume you have to be naked to have a beautiful pregnancy portrait. If you are a modest person you can stay mostly covered. Also, don't think you have to miss out just because you're a larger size or have stretch marks. You won't believe the results that can be achieved with a little digital retouching. It's like magic!