If you sit in front of a computer screen all day, make sure to sit up straight and keep your feet slightly raised off the floor on a footstool or other low object. Don't sit for long periods; get up and walk around the office or step outside for a break at least every half hour.

Wear flat, comfortable shoes. As your stomach grows and your balance shifts, a pair of high heels will only make your posture worse.

Always bend from your knees and lift objects and children from a crouching position to minimize the stress on your back. Let someone else lift heavy objects; this is not the time to risk throwing your back out completely.

Start an exercise programme early in pregnancy, one that includes stretches that strengthen and stretch muscles that support the back and legs. Don't worry if you're well past your first trimester; you can start a simple stretching routine at any time.
Swimming is a particularly good choice for pregnant women because it strengthens your lower back muscles, and the buoyancy of the water takes the strain off your joints and ligaments. Avoid doing breaststroke, though, as this can affect your lower back joint.