Acute fatty liver ofpregnancy (AFLP), also known as acute yellow hepatic atrophy, is a rare obstetric emergency with rapid onset and dangerous condition, seriously endangering the life of mother and child and easily causing maternal and infant death. The incidence rate is 1/7000 to 1/20000, mostly in late pregnancy, with an average gestational age of 35 to 36 weeks. The specific etiology and pathogenesis of the disease are still unclear, but its pathology is characterized by a large number of microvesicular fatty infiltrations of hepatocytes in a short period of time, without inflammatory or necrotic changes, and normal structure of liver lobules. It is easily ignored by obstetricians and patients because patients initially have only non-specific symptoms such as nausea, malaise and general malaise. However, the disease changes rapidly, and patients can develop liver failure, progressive jaundice, coagulation dysfunction, acute renal failure, and even death within a short period of time. Therefore, early diagnosis, timely termination of pregnancy and active treatment with symptomatic support are necessary to reduce maternal and child mortality. The exact etiology and pathogenesis of AFLP is not clear, but it may be related to enzymatic defects in the mitochondrial fatty acid oxidation process. the pathogenesis of AFLP is also associated with abnormal maternal hormone levels, oxidative stress, pathogenic microbial infections and malnutrition, which may also be the causative factors of the disease. 3. Diagnosis (1) Risk factors: primiparity, male pregnancy, multiple pregnancy and preeclampsia. (2) Clinical manifestations: the disease can develop at any time during late pregnancy, with an average gestational age of 35-36 weeks. Most patients have nonspecific prodromal symptoms several days to weeks before diagnosis, including nausea, vomiting, anorexia, general malaise, headache and right upper abdominal pain, among which vomiting and abdominal pain are most common, and irritability and thirst may also occur. Jaundice appears following gastrointestinal symptoms and deepens progressively, usually without pruritus. The disease changes rapidly and manifestations of multi-system and multi-organ insufficiency appear: liver and renal failure, diffuse intravascular coagulation, gastrointestinal bleeding, oliguria, pre-eclampsia, tachycardia and impaired consciousness, which may progress to hepatic encephalopathy, coma, shock and even death in critical cases. AFLP can cause serious harm to the fetus. The metabolic acidosis, azotemia and various toxic substances produced by liver and kidney failure can directly endanger the fetus, leading to preterm birth, stillbirth and stillbirth, and the perinatal morbidity and mortality are extremely high. (3) Ancillary tests: skipped, professionals learn, more complicated. (4). Diagnosis and differential diagnosis: The clinical manifestations are non-specific at the early stage of the disease, making early diagnosis difficult. In addition to the diagnosis based on medical history and clinical features, ancillary examinations are the main basis. For patients with suspected AFLP, early diagnosis and timely termination of pregnancy are the keys to improve maternal and child outcomes. The diagnostic criteria are as follows: (1) Vomiting. (2) Abdominal pain. (3) Polyuria/irritable thirst. (4) Encephalopathy. (5) Elevated bilirubin (>14 μmol/L). (6) Hypoglycemia (<4mmol/L). (7) Elevated uric acid (>340μmol/L). (8) Leukocytosis (>11×109/L). (9) Ascites or “bright liver” visible on ultrasound. (10) Elevated ALT or AST (>42 U/L). (11) Elevated blood ammonia (>47 μmol/L). (12) Renal impairment (creatinine >150μmol/L). (13) Coagulation abnormalities (PT>14s or APTT>34s). (14) Liver biopsy suggestive of microvesicular steatosis. In the absence of other diseases that can explain, the diagnosis is confirmed by meeting 6 or more of the above indicators. AFLP mostly occurs in late pregnancy with varying severity and can coexist with other diseases in late pregnancy, requiring differential diagnosis with pre-eclampsia, HELLP syndrome, acute viral hepatitis and intrahepatic cholestasis in pregnancy. 4. Obstetric management and treatment: AFLP can cause maternal systemic multi-organ failure in obstetric emergencies and must be given high priority. AFLP does not subside on its own after delivery, but if the timing of termination of pregnancy is delayed, patients can develop serious life-threatening complications such as coagulation dysfunction, hepatorenal syndrome, and hepatic encephalopathy at any time. Since the disease is associated with pregnancy and the liver is a highly regenerative organ, early diagnosis, timely termination of pregnancy and maximum supportive therapy are still the three basic principles in the treatment of AFLP. (1). Obstetric management: The treatment of AFLP requires the cooperation of multidisciplinary professionals from obstetrics, ICU, infection, anesthesiology, neonatology, etc. No prenatal cure has been reported. Once the diagnosis of AFLP is made, immediate preparation for termination of pregnancy is recommended (top priority). Cesarean delivery is almost always required immediately. AFLP often has coagulation disorders, and cesarean delivery requires vigilance for postpartum hemorrhage and transfer of the patient to the intensive care unit for further treatment after the procedure. It is important to realize that termination of pregnancy does not mean improvement of the disease and that active prevention of coagulation disorders, postpartum haemorrhage, liver and renal failure and metabolic disorders is still needed after delivery. (2). Management plan for liver failure: ICU, internal medicine and hepatology are needed for joint treatment. The organization of multidisciplinary consultation and treatment is the key to successful resuscitation. Artificial liver support system or blood purification techniques are effective in treating patients with AFLP combined with multiple complications. Key tip: AFLP is a critical obstetric condition that seriously endangers the health of mother and child. Once AFLP is suspected, a clear diagnosis should be made and the pregnancy should be terminated by cesarean section as soon as possible and transferred to ICU for continued monitoring after surgery. Early diagnosis, timely termination of pregnancy and maximum supportive care remain the three basic principles in the treatment of AFLP.