The chances of excess amniotic fluid malformation at 37 weeks are about 20% to 50%. In addition to fetal malformations, excessive amniotic fluid can also be caused by gestational diabetes, placental cord pathology, etc. Ultrasound and laboratory tests are recommended under the supervision of a doctor to determine the cause of the condition. Excessive amniotic fluid refers to the amount of amniotic fluid exceeding 2,000ml during pregnancy, with an incidence of 0.5%~1%. Fetal anomalies cause excessive amniotic fluid in 20%~50%, or gestational diabetes, placental umbilical cord lesions and other causes of excessive amniotic fluid. 1. Fetal malformations: mostly seen in neurological and digestive tract abnormalities. (1) Neurological anomalies: mainly anencephaly, spina bifida and other neural tube defects, which cause excessive amniotic fluid due to the exposure of the cerebrospinal membrane and increased exudate. (2) Structural anomalies of the digestive tract: mainly atresia of the esophagus and duodenum, which prevents the fetus from swallowing amniotic fluid, leading to accumulation of amniotic fluid and excessive amniotic fluid. (2) Gestational diabetes mellitus: mainly due to maternal hyperglycemia, fetal blood glucose increases, producing hyperosmolar diuresis and increasing the exudation of placental membranes, leading to amniotic fluid overflow. 3. Placental umbilical cord lesions: when the diameter of placental chorioangioma is 1cm, it is combined with excessive amniotic fluid. It is recommended to consult the doctor in time, measure the amount of amniotic fluid with the help of ultrasound and laboratory tests to understand the condition of the fetus, clarify the cause of the disease, and follow the doctor’s instructions to deal with the treatment.