It is recommended to lie on the side in the second trimester of pregnancy, and avoid lying down, so as to avoid the increasing uterus pressing on the inferior vena cava, causing insufficient blood flow back to the heart to cause discomfort. Due to the gradual increase of the fetus in the second trimester of pregnancy, a certain amount of pressure is exerted on the mother’s body, which leads to various uncomfortable feelings in the second trimester of pregnancy, especially the phenomenon of feeling breathless when lying down is very common, which is due to the increasing uterus compressing the inferior vena cava, so try to sleep on the side of the bed, which will make you feel more comfortable. If you occasionally feel comfortable lying flat, as long as you can breathe well, there is no effect on the fetus. It is recommended to change the position of the body when sleeping in the second trimester, and once you feel uncomfortable, you should go to the obstetrician for examination in time and standardized treatment under the guidance of the doctor.