Pregnant women should sleep on their left side, which is good for blood return, and can also improve the uterus’ right-handedness. In the middle and late stages of pregnancy, the pregnant woman’s uterus will gradually increase in size as the weeks of pregnancy grow, and the oversized uterus may compress the inferior vena cava, which will easily cause obstruction of blood reflux. Pregnant women choose to sleep on the left side of the bed, can reduce the oversized uterus on the pressure of the inferior vena cava, is conducive to blood flow. After pregnancy, the uterus is mostly in the state of right-handedness, pregnant women sleeping on the left side can make the enlarged uterus turn to the left side, it may make the uterus right-handedness get some improvement. Pregnant women need to be under the guidance of obstetricians and gynecologists, according to the individual’s own situation to choose the appropriate sleeping position to sleep.