Sleeping on the left side is usually better in late pregnancy, but which position is more comfortable depends on the individual. Usually, adopting the left side lying position in late pregnancy can improve the situation of uterine right rotation, and also can ensure the blood flow and oxygen supply to the fetus, which is beneficial to the growth and development of the fetus. And take the left side lying position is also conducive to fetal absorption of nutrients and discharge of waste, carbon dioxide, etc., but also to avoid the inferior vena cava is compressed, so as to reduce the limb edema situation. However, this is not absolute, generally pregnant women can alternate between left and right side lying, but should not be maintained for a long time right side lying position and supine position, may affect the blood supply of the fetus, some fetuses may also have chronic hypoxia. And some patients may also experience edema, panic, dizziness, weakness of the limbs, pallor and other symptoms. In summary, the comfortable sleeping position in late pregnancy varies from person to person, pregnant women according to their own situation to choose the right and left side of the sleeping position alternately, and try to avoid long-term to keep the flat position or the right side of the lying position.