Fetal hydronephrosis is often found during pregnancy tests. There are many causes of fetal hydronephrosis, and the following aspects are common: some can recover on their own, for example, if the fetal bladder is filled with a large amount of urine, it will increase the pressure on the kidneys, leading to hydronephrosis, which can slowly subside with the elimination of urine; in addition, some lesions may lead to dysregulation of the contraction rhythm of the ureter, resulting in In addition, some lesions may lead to dysregulation of the ureteral contraction rhythm, resulting in fetal hydronephrosis. This condition can recover on its own as the fetus slowly develops or after the birth of the fetus, when the contraction rhythm of the ureter is restored. The prognosis of congenital hydronephrosis depends mainly on the cause and the degree of development, so we need to wait for the birth of the baby and then carry out the relevant examination. The common possible causes are: 1. segmental dysfunction and intrinsic ureteral stenosis, such as dysplasia of the muscles at the junction of the renal pelvis and ureter, leading to local obstruction and hydrocele, 2. distortion and adhesion of the ureter, due to developmental problems, leading to abnormal position of the ureter, distortion and adhesion, leading to hydrocele, 3. abnormal vascular compression or ectopic ureter, polycystic kidney, etc., may lead to hydrocele. polycystic kidney, etc., may lead to the appearance of hydronephrosis. If you find hydrocele in your fetus during the pregnancy test, you must communicate with your obstetrician and pediatrician to learn more about the actual condition of the fetus and then consider the treatment plan later.