Amniotic fluid embolism may occur in both normal and cesarean deliveries. The overall incidence of amniotic fluid embolism is relatively low, but once it occurs, it is an extremely dangerous disease. Amniotic fluid embolism refers to the sudden entry of amniotic fluid into the maternal circulation during labor and delivery, causing serious complications during delivery such as acute pulmonary embolism, anaphylaxis, diffuse intravascular coagulation, renal failure or sudden death, with a mortality rate of 19% to 86%. The current medical support is significantly better than 20 years ago. If it happened 10-20 years ago, the success rate of amniotic fluid embolism resuscitation was very low and most of them might not be resuscitated. Amniotic fluid embolism is caused by a very large amount of tangible substances in contaminated amniotic fluid, such as fetal hair, keratinized epithelium, fetal lipids, fetal feces and procoagulant substances, entering the maternal circulation and causing disseminated intravascular coagulation, or DIC, as well as anaphylaxis. In recent years, it is believed that amniotic fluid embolism is mainly an allergic reaction, because after the amniotic fluid enters the maternal circulation, it causes a series of allergic reactions of the mother to fetal antigens, which is called the allergic reaction syndrome of pregnancy. Once amniotic fluid embolism occurs, the onset is rapid, the development is rapid, and the mortality rate is extremely high. The causes are related to the high force in the amniotic cavity, the opening of blood sinus, and the rupture of fetal membranes. The clinical manifestations are sudden choking, breath-holding, chest tightness, followed by a sharp drop in blood pressure, oxygen saturation, and even cardiac and respiratory arrest.