Strengthening your core helps stabilize your torso, which can prevent back discomfort as your pregnancy progresses.
Sit up straight with your knees bent, heels down and toes lifted. Reach both arms in front of you at eye level as you pull your abs in and do a Kegel. Holding the Kegel, inhale, then exhale as you lean back, hinging from your hips. Keeping your torso straight, turn slightly to the right and reach your right arm to the side. Inhale as you return to the starting position. Do 6 reps on each side, working up to 10.