Pediatric hydronephrosis is one of the common malformations in pediatric urology. More and more pediatric hydronephrosis is detected and diagnosed early in fetal life, and then strictly followed up and managed in time, making it a proactive diagnostic and therapeutic process that greatly reduces the occurrence of serious conditions and maximizes the protection of renal function. How exactly should we face the discovery of hydronephrosis in the fetal stage? As a professional pediatric surgeon the following suggestions, please refer to: 1. facing the choice of fetus, continue the pregnancy? Or abort? Hydrocele found in the fetal period should be a malformation with a relatively low incidence. There are many reasons for the appearance of hydrocele in the fetal period, most of them belong to physiological hydrocele, which accounts for about 60-70% of the total number of hydrocele in the fetal period. With pathological hydrocele, mothers and fathers are more worried in most cases due to the possibility of needing surgical intervention, especially for the prognosis of the child. In fact, clinically, less than 10% of the total number of children born with hydrocele who really need surgery for this disease are found in the fetal period, and the majority of children do not need surgery. 2.If you choose to continue the pregnancy, you will face a second problem: how to spend the pregnancy period? The main interventions during pregnancy in China are still follow-up, and intrauterine surgery is not recommended. 3.Postnatal follow-up program and timing of surgical treatment Postnatal follow-up is divided into two parts: fixed follow-up and dynamic follow-up according to the degree of hydrocele during fetal life. Fixed follow-up refers to the first two fixed ultrasound examinations: the first ultrasound examination after birth is usually required before the mother is discharged from the hospital (about 3-5 days after the birth of the child) for children with hydrocele found in the fetal period, and the second ultrasound examination after birth, which we mostly recommend on the 42nd day after birth. Dynamic follow-up is divided into three levels according to the degree of hydronephrosis or the trend of change: general follow-up, intensive follow-up and close follow-up. (1) General follow-up: Analysis of the ultrasound results of the two examinations: Generally, most of the separation of the collecting system or the liquid dark area of the renal pelvis under ultrasound is less than 1-1.5 cm, and some of them may fluctuate more than 2.0 cm, but the overall trend of change is not much, or there is no increase, which can be considered as “mild hydronephrosis”. Most of these children have physiological hydronephrosis, which can subside on its own, so there is no need to worry about it; of course, there are also children with persistent hydronephrosis, but there is no tendency to worsen it, so you can also rest assured. The interval between the third and subsequent follow-ups of these children can be extended accordingly, until the child is 3 months old and 1 year old …… If there is still no change, you can extend it further to the time of the physical examination for schooling. (2) Intensified follow-up: Children with a separation of the collecting system greater than 2 cm before birth and still greater than 2 cm after birth, or children with a tendency to increase in size as analyzed by two ultrasound examinations, need to be intensively followed up. It is recommended to fix the follow-up time with an interval of 2-3 months. This kind of follow-up not only does not increase the burden of follow-up for the child, but also enables timely understanding of the changes of fluid accumulation, so as to strive for appropriate timing for surgical intervention and prevent further aggravation of renal function damage. (3) Close follow-up: Children with a separation of the collecting system greater than 2-3 cm and a thinning of the renal cortex or parenchyma before birth, especially those with a renal cortex thickness of less than 0.5 cm, or those with dilated renal calyces, are cases that should be given sufficient attention. Active follow-up, which we generally call close follow-up or close follow-up, is required in collaboration with the parents, with a fixed follow-up period of 1 month, requiring ultrasonography every month, and MRI or CT imaging or isotopes are recommended, and sometimes even serological monitoring of renal function is required. The main purpose of close follow-up in such cases is to synthesize and analyze the various test results in the follow-up and to perform surgical intervention as early as possible to save the kidney function to the maximum extent. As long as moms and dads strictly follow the pediatric surgeon’s orders and follow up regularly, I believe their children will recover successfully!