Hypotension is the most common complications after spinal anesthesia especially in pregnant patients who undergoing cesarean section. Position during spinal anesthesia may be altering the hemodynamic. For right lateral decubitus, the enlarged uterus compresses inferior vena cava that may decrease venous return and cardiac output. This leads to hypotension.The hypothesis is the right lateral position during spinal anesthesia in pregnant women will be had hemodynamic changing more than the left lateral position. This objective is to compare hemodynamic change between left and right lateral position during spinal anesthesia in pregnant women undergoing cesarean section.