If a woman is found to have ascites on ultrasound during pregnancy, the exact cause should be determined based on the amount of ascites and other accompanying symptoms of the pregnant woman. If the pregnant woman does not have any discomfort, only a small amount of ascites, and the liver function test does not have any abnormality, but she had malnutrition before pregnancy, it should be considered that the formation of a small amount of ascites is caused by hypoproteinemia. There is no need to carry out special treatment for the time being, we should continue to review the ultrasound to see the growth and change of fluid, and at the same time, actively supplement the nutrition to correct the anemia and malnutrition. If the amount of ascites is relatively large, accompanied by obvious pain in the liver area and nausea, anorexia and other discomforts, it should be considered that it may be caused by liver diseases, such as cirrhosis or acute hepatitis. At the same time, malignant tumors of the pelvis and abdominal cavity can also cause ascites during pregnancy, such as common ovarian cancer or liver cancer.