Improve your posture
Backache is one of the most common pregnancy niggles. There are many causes, but one of the main ones is bad posture caused primarily by the weight of your bump. This exercise should get you in good habits.
Stand with your feet hip-distance apart, making sure your knees are soft. Feel the weight of your feet on the floor and feel your trunk lifted and open.
Tilt your pelvis forward, your tailbone down towards the decking, and pull your baby up and in towards your spine. Make sure you have a natural curve in your back - it shouldn't be vaulted. Lengthen through the spine and aim for a nice straight back. Keep your shoulders back and down, and imagine you have a string pulling your head upright.