Things You'll Need
Polyester or soft denim
Inflatable beach ball
A fake pregnancy belly makes a costume sure to impress and might garner you those coveted "oohs" and "aahs." You could buy an expensive silicone belly suit online, or try this fun and creative way to make a baby bump with simple materials lying around the house.
Cut out two rectangles of fabric, each approximately 12 to 13 inches wide and 2 feet long. You can make the pieces bigger if you have a larger frame or smaller if you don't need as much coverage.
Blow up your beach ball roughly half full. Set the ball on top of the first fabric, positioning it in the center. Lay the second fabric horizontally over the beach ball so that it fits perpendicular to the bottom layer. Pin the sides of the fabric to the bottom piece. Pin the bottom corners in pleats to work around the curve of the ball and then pin a straight line along the bottom of the rectangle.
Sew the sides and bottom together with the beach ball still inside. The backside of the "pillow" you are creating should be smooth, without pleats, and the front side should have the pleated corners.
Slip the ball out through the top and pin the two top corners in pleats. These pleats should be smaller than the bottom corners since this is the narrowing upward part of the belly. Leave an opening at the very top for stuffing.
Stuff the pillow through the top with the fiber fill, adding more stuffing for firmness or less for lumpiness. Sew the top edge and corner pleats to seal the pillow. Trim extra fabric along the perimeter so nothing unnecessary will stick out.
Cut the elastic band to match your upper-waist dimensions and then sew it to the underside of the fake belly, making a belt-like loop. The band should slip on over your hips so that the pillow nestles against your stomach. You can also wedge the pillow inside a pre-sized maternity belt, such as a Bellaband, to avoid further sewing.
Consider dressing up the exterior of your fake pregnant belly to maximize dramatic effect. Add some fake blood and tiny protruding limbs for a zombie baby, or a jack-o-lantern face for a pumpkin pregnancy.