Sit upright on a stability ball.
If your pregnancy bump is larger it often helps to sit nearer the front of the ball.
Place your feet flat on the floor with your knees and hips bent to 90 degrees.
Gently tighten you tummy muscle and pull your shoulder blades back and down.
Tilt you pelvis forwards arching your back and sticking your tail bone out behind you.
Slump down, rolling your tail bone underneath and rounding your back.
Keep your shoulders and upper back still during the movement.