"My Water Broke" baby shower game. Freeze plastic ‘babies’ in ice cubes. Put a cube in everyone's drink. During the shower when someone’s ice melts enough to let the baby float – they yell “My Water Broke!” A prize is given – and/or hilarity ensues!
Games - Bottle Chugging I don't know if this is the crowd for this, but sounds fun to me. Fill baby bottles with your drink of choice. Make it a bit more fun for non-pregnant guests by adding some booze, then have guests race to chug them down.