In the late stages of pregnancy, it is recommended that pregnant women should preferably lie on their sides, of which the left lateral position is better. The left side lying position can improve the uterus right rotation state, reduce the uterus on the abdominal aorta compression, improve the blood circulation of the placenta, can promote the growth and development of the fetus, but also can reduce the probability of the occurrence of supine hypotension syndrome. Pregnant women to late pregnancy uterus significantly increased, this situation is not suitable for lying down, because lying down will compress the abdominal aorta, which will lead to low blood pressure, nausea, chest tightness and other uncomfortable situations. So in late pregnancy side lying position is a better position, the right side lying position can also be.