Occasional sleeping on the right side during pregnancy will not have much effect on the fetus. If you sleep on your right side for a long time, it may lead to fetal hypoxia, intrauterine distress and other problems. At the beginning of pregnancy, the embryo and uterus are still small, pregnant women can lie flat or sleep on the right or left side, which will not affect the development of the fetus. In the middle and late stages of pregnancy, it is recommended to alternate between sleeping on the left and right side, or sleeping on the left side, long-term right-side sleep may compress the inferior vena cava, causing a decrease in the blood flow back to the heart, the placenta is underperfused, fetal hypoxia, and in severe cases, fetal intrauterine distress occurs. It is recommended to sleep on the left side of the late pregnancy, in addition to regular obstetric examination, every day you need to count the fetal movement, once the fetal movement is abnormal, you need to consider whether there is a lack of oxygen and other problems, timely medical consultation with a professional doctor.