In vitro ascites, most often caused by ovarian hyperstimulation syndrome or abnormal liver function. The most common cause of IVF ascites is ovarian hyperstimulation syndrome. It is caused by the use of high doses of gonadotropins to stimulate the ovaries and retrieve eggs during the IVF process, and manifests itself as an increase in the permeability of the capillaries of the ovaries after cystic enlargement of the ovaries, and the infiltration of bodily fluids from the blood vessels to the outside of the blood vessels. There are different degrees of ovarian hyperstimulation syndrome; in mild cases, it may be asymptomatic or only manifested as nausea, vomiting, abdominal distension, diarrhea, etc.; in severe cases, it may show obvious chest and abdominal fluid, cerebral thrombosis, liver and kidney function damage, and in severe cases, respiratory distress and even death. In addition, if you have abnormal liver function such as hepatitis, it can also cause ascites during the IVF process. If you have any other questions, it is recommended to consult a professional doctor for guidance.