You can use a fake maternity belly to create many comical Halloween costumes, from a generic pregnant woman to a strange pregnant man. Dress as a pregnant Angelina Jolie and partner with a Brad Pitt lookalike carrying several dolls to emulate the famously kid-obsessed couple, or carry several dolls and go as the "Octo-mom." While you can purchase pre-made pregnancy bellies to wear, making your own is simple and inexpensive.
Cut an oval from the polyester batting that is slightly wider than your waist.
Cut a second oval that is 1/2 inch smaller than the first oval and place it on top of the first oval. Continue cutting ovals, each 1/2 inch smaller than the last, and stack them on top of each other until you get the size of pregnancy bump you want.
Cut two pieces of knit fabric that are at least 2 inches larger than your largest batting oval. You can purchase inexpensive cotton fabric at a craft store or use an old T-shirt.
Place one piece of fabric under the stack of batting ovals and one on top. Stitch the two pieces of fabric together all the way around the batting ovals using needle and thread to create the pregnancy bump. Trim off any excess fabric. For a smooth look, the smallest oval of batting will go against your stomach when you wear the belly.
Stitch a piece of elastic to the middle of one side of the pregnancy bump. Hold the bump against your belly and pull the elastic around your back to the other side of the pregnancy bump.
Make a pencil mark on the elastic where it meets the other side of the pregnancy bump, making sure the elastic is stretched enough to create a snug fit so your bump will stay in place.
Remove the bump and stitch the elastic to the other side where marked. Trim off any excess elastic.
Instead of polyester batting, you can cut ovals from an old foam or fabric mattress pad to create the maternity bump.