You can't prevent it. All you can do is watch for it. It often runs in families. Girls are four times more likely than boys to have it, and it is much more likely to progress and require treatment in girls. The ribs on the side toward the curve become pushed together, and on the other side they're spread apart.
Mild scoliosis is barely noticeable.
But when it becomes severe, it can cause back pain, fatigue, nerve problems, disfigurement, and heart and lung problems if these organs are crowded into too little space. Scoliosis usually appears in late childhood or the early teens. It can progress rapidly during the growth spurt, so about half of US states require screening beginning in fifth or sixth grade. Curvature of the vertebrae may be visible. One shoulder blade is often more prominent than the other.