Generally speaking, pregnant women in early and mid-pregnancy, the position of sleeping at night, there is no great impact on the child, as long as you do not sleep on your back. To the late pregnancy is generally recommended to sleep on the left side of the position, if long-term lying or right side of the position there may be obstruction of vena cava reflux. Because of the general early and mid-pregnancy, the fetus is still relatively small, there are no strict rules for the sleeping position, as long as the pregnant woman feels comfortable. However, in late pregnancy, the fetus will gradually increase in size, and the uterus of the pregnant woman will also increase in size, which will easily cause pressure on the inferior vena cava, so it is recommended to lie on the left side. If the long-term bad sleeping position may lead to a decrease in the amount of return blood, it is possible that the pregnant woman will have low blood pressure, intrauterine distress and other conditions. If any uncomfortable symptoms occur during pregnancy, it is recommended to consult a doctor in time to treat the symptoms.