I need to film a scene with a pregnant girl. In the scene the girl will move her shirt revealing the belly. So I need a way to fake a pregnant belly with the real skin look and color.
Obviously a pillow or any kind of stuffing wouldn't work for this kind of scene.
Any suggestions?

You can buy pregnancy pillows - they look very much like the real thing.

Pregnant body double?

Latex and flesh color make up. That's how its done in Hollywood. But there is another way. You could use Mortician's Wax (yes, that's the stuff used in funeral homes to make dead people look good.) It's a soft, flesh colored wax that is very moldable. You could flatten it out, like pizza dough, then lay it over a dome shaped object to get the right form, carve a belly button in the wax, then lay it on your actress' belly with a little padding underneath for support, and then smooth out and blend the edges to her actual skin. Add a little powder make up to match skin tones, and this should look very real. Now, keep in mind, it might be too soft for multiple uses or too many takes.

Visit the website: www.bellymake.com
There you will find what you are looking.

This thread is over a year old - I'm sure OP has an answer by now.