Sleeping in the right lateral position is also not conducive to the development of the fetus, because the uterus is constantly expanding and other abdominal organs are squeezed. Sometimes, the sigmoid colon in the lower abdominal cavity is squeezed, which will make the expectant mother's uterus rotate to the right to varying degrees, thus making the ligaments and mesangium that maintain the normal position of the uterus in a state of tension. The blood vessels that nourish the uterus in the mesentery will be pulled, which will affect the oxygen supply of the fetus, thus causing chronic hypoxia of the fetus and suffocation of the fetus in severe cases.