Though sit-ups may be out when you have a bump, you can still strengthen your core – with keels! Sara Haley, creator of Expecting More®, a workout DVD, explains how to do these pelvic floor exercises: Contract the muscles that you would use to stop the flow of urine or to halt gas. Hold, release, and repeat 10 times (or more!) every day. “Just like biceps curls aren’t the only way to tone arms, there are many ways to strengthen the core.” Haley says.