Cystic occupancy of the right kidney in the fetus may indicate a renal cyst or liver cyst. Renal cyst: During the development of the fetus’s kidneys, cystic masses may appear, and at this time, the ultrasound findings may show cystic occupancy of the right kidney. It is usually based on the location and size of the cysts present, etc., to comprehensively determine whether treatment is needed. If the cyst is small and there is no abnormality in the development of other fetal systems, it can be observed conservatively; if there is a more serious condition such as hydronephrosis on the opposite side of the kidneys, further treatment may be needed. 2. Liver cysts: During the development of the fetal liver, if the cysts on the surface of the liver protrude towards the lower part of the liver, then the cysts may be located between the liver and the right kidney, and the ultrasound may suggest cystic occupancy of the kidney, and the specific situation needs to be judged together with the results of other examinations. In this case, if the size of the cyst is small and no other abnormalities are seen in the follow-up examination, then the cyst is likely to be benign and can be observed dynamically. After the baby is born, if the size of the cyst does not continue to increase, it can be rechecked regularly; however, if it grows rapidly or causes abnormalities in the baby’s digestive function, interventional treatment can be considered. Regular checkups should be performed during pregnancy to monitor the health of the mother and the development of the fetus.