Late pregnancy can sleep on the right side, but it is recommended that the left side of the lying position, long-term hold a position when fatigue occurs, can be left and right alternating side lying. As the weeks of pregnancy increase, the uterus continues to grow, most of the different degrees of right-handedness, while the surrounding ligaments, tethered membranes are also in a state of tension, which contains blood vessels are also subject to extrusion, reducing the blood supply to the uterus. The left side of the lying position can reduce the uterus right rotation, alleviate the situation of insufficient blood supply to the uterus, but the night has been to maintain the same sleeping position is more tired, can be alternated between left and right lying position. Sleeping position during pregnancy should avoid prone position and supine position, prone position can directly press on the enlarged uterus, right supine position, the enlarged uterus can compress the abdominal aorta, thus supine hypotension.