Excessive amniotic fluid is defined as the amount of amniotic fluid exceeding 2,000 ml during pregnancy. Amniotic fluid is the fluid that fills the amniotic cavity, more than 90% of which is water, and also contains minerals, urea, uric acid and fetal epithelial cells, etc., which protects the fetus and reduces maternal damage. The production and absorption of amniotic fluid in normal pregnancy is in dynamic balance, if the production and absorption of amniotic fluid is out of balance, it will lead to abnormal amniotic fluid volume. If the amount of amniotic fluid exceeds 2,000 ml during pregnancy, it is considered excessive amniotic fluid. The amount of amniotic fluid can be measured by ultrasound. The criteria for excessive amniotic fluid under ultrasound examination include the vertical depth of the darkest zone of amniotic fluid and the amniotic fluid index. If the vertical depth of the darkest area of amniotic fluid is greater than or equal to 8cm, or the amniotic fluid index is greater than or equal to 25cm, then the diagnosis of amniotic fluid overload can be confirmed. Once a pregnant woman is diagnosed with amniotic fluid, she needs to go to the hospital immediately for further examination to identify the cause of the disease and under the guidance of the doctor for treatment.