The main causes of dyspnea at night during 36 weeks of pregnancy include diaphragm elevation, increased oxygen consumption and blood volume, and edema of the respiratory mucosa. 1. 36 weeks of pregnancy belongs to the late stage of pregnancy, the enlarged uterus will cause the diaphragm to be elevated and compress the chest cavity, which may cause dyspnea. 2. The enlarged uterus will compress the inferior vena cava when the pregnant woman sleeps, causing obstruction of blood circulation and manifestation of hypoxia, which is a symptom of dyspnea. 3. The increase of blood volume in late pregnancy may cause bruising and edema of the lungs, which may lead to the decrease of the respiratory function of the lungs, resulting in the manifestation of dyspnea. 4. Late pregnancy due to lung stasis and edema may cause congestion and edema of the respiratory mucosa, which in turn aggravates the symptoms of dyspnea. If you have trouble breathing at night during your 36th week of pregnancy, it is recommended that you change your sleeping position or sit up for a period of time to relieve it. If it persists without relief, prompt medical attention is needed.