If newborns have double kidney separation, it can be manifested as hydronephrosis, renal dysfunction, as follows: 1. Hydronephrosis: after newborns have double kidney separation, the drainage function of the renal system will be obviously impaired, and the water and fluid in the kidneys will accumulate in the renal system, which will cause hydronephrosis. If the amount of hydronephrosis is small, it can be self-absorbed by the body. If there is more water in the kidneys, it will cause severe hydronephrosis; 2. Renal dysfunction: as the separation of the two kidneys of newborns will cause hydronephrosis, the hydronephrosis will continue to squeeze the kidneys, which affects the renal function. After the newborn’s kidney function is abnormal, it will cause the increase of urea and creatinine.