Amniotic fluid embolism is the process of pulmonary hypertension, hypoxemia, circulatory failure, diffuse intravascular coagulation and multi-organ failure caused by the entry of amniotic fluid into the maternal circulation. It is characterized by rapid onset, dangerous condition, unpredictability and high mortality rate, and is an extremely serious complication during pregnancy and childbirth. Advanced primiparity, menstruation, cervical laceration, uterine rupture, excessive amniotic fluid, multiple pregnancies, excessive uterine contractions, emergency delivery, premature rupture of membranes, placenta praevia, uterine rupture, cesarean section and curettage may be predisposing factors for amniotic fluid embolism. The incidence rate is 1.9-7.7/100,000, and the mortality rate is 19%-86%. 1. Typical amniotic fluid embolism: characterized by sudden onset of hypoxemia, hypotension (blood pressure does not match blood loss) and coagulation dysfunction, also known as the triad of amniotic fluid embolism. (1) Prodromal symptoms: 30-40% of patients will present with nonspecific prodromal symptoms, such as shortness of breath, chest pain, breath-holding, chills, choking cough, dizziness, fever, panic, nausea, vomiting, numbness, pins-and-needles sensation, anxiety, irritability and near-death feeling, deceleration of fetal heartbeat, and loss of baseline fetal heart variability. (2) Cardiopulmonary failure and shock: patients present with sudden respiratory distress or cyanosis, tachycardia, hypotension, convulsions, loss of consciousness or coma; in severe cases, the mother dies suddenly within a few minutes. (3) Coagulation dysfunction: the appearance of systemic bleeding tendency, mainly uterine bleeding, such as incisional bleeding, systemic skin and mucous membrane bleeding, needle eye bleeding, hematuria, gastrointestinal hemorrhage, etc. (4) Acute renal failure and other systemic organs can be damaged. 2.Atypical amniotic fluid embolism: The patient only presents hypotension, arrhythmia, shortness of breath, convulsions, acute fetal distress, postpartum hemorrhage, coagulation dysfunction or the precursor symptoms of typical amniotic fluid embolism. Amniotic fluid embolism occurs in 70% of vaginal deliveries and in 19% of cesarean deliveries. It occurs mostly between 2 hours before and 30 minutes after delivery, and rarely during mid-pregnancy induction, amniocentesis and trauma. It also has a rapid onset and a high mortality rate.