Sciatica is a shooting, burning pain that can radiate from hip to foot. This pain is caused by compression of the sciatic nerve, the large nerve that innervates the lower half of the body. The sciatic nerve runs below the uterus. It can become compressed or irritated by the weight of the baby or by changes in posture due to your growing baby. By realigning your vertebrae and putting everything back where it belongs, your chiropractor can reduce compression of your sciatic nerve reducing the pain.