Many mothers-to-be panic at once when they see the ultrasound report that the fetus has hydronephrosis during their maternity checkup. What is hydronephrosis? Why does my baby have hydronephrosis? Can I still have the baby? …My heart was instantly filled with various questions, and I was anxious throughout my pregnancy. What should I do if I find hydrocele in my fetus? Don’t panic, I will answer several questions for all mothers-to-be. Q: What is hydronephrosis? A: Kidney is the place where urine is produced (of course, everyone knows this). As shown in the picture below, the kidney is shaped like a lentil and consists of the renal cortex and structures such as the renal cone and calyces; several calyces converge to form the calyces, which eventually converge to form the renal pelvis, which gradually becomes thinner and connected to the ureter. Why do we need to talk about these parts? It is to show you how the kidney works. The renal cortex and the renal cone are responsible for producing urine, while the calyces, calyces and pelvis are responsible for transporting it. The various stations that urine passes through along the way are what doctors often refer to as the urinary system. If there is a “barrier” anywhere along the way, urine cannot be discharged smoothly, it will accumulate in the kidneys. Just like blowing up a balloon, the more air the bigger the balloon is, the thinner the skin is; similarly, the more urine the kidneys hold up, the thinner the kidneys will become, and an ultrasound will reveal fluid in the kidneys. Q：What should I do if hydronephrosis is found in labor and delivery? A: 99% or even 100% of fetal hydronephrosis found during maternity checkups can be cured after birth. In the past, some mothers-to-be were induced because of fetal hydronephrosis, which is really undesirable. Of course, there is a special case, that is, the fetus is found to have bilateral hydronephrosis with reduced amniotic fluid, this situation is likely to have posterior urethral valves or urethral atresia, this situation needs to be treated as soon as possible after birth to avoid renal insufficiency or urinary tract infections, the latter occurrence is low, even if the parents do not actively give up, the fetus is difficult to survive. Generally speaking, unilateral hydronephrosis or bilateral pelvic dilatation is not too severe, and there is no reduction of amniotic fluid, such children will be fine after birth after treatment, so parents need not worry too much. Especially for hydrocele detected in fetus, from our follow-up observation, about 60% of fetuses are physiological hydrocele, which means that they will be fine naturally without any treatment after birth. Q: How to monitor the condition of fetal hydronephrosis when it is found? A: If fetal hydrocele is found during labor and delivery, the mother-to-be just needs to have regular labor and delivery checkups and regular ultrasound to monitor the degree of hydrocele. If the fetal renal pelvis becomes more dilated and the renal cortex becomes thinner during maternity checkup, it means that the hydronephrosis is getting more and more serious, so it is necessary to go to the pediatric urology department in time to seek treatment. At present, there are no cases reported in the domestic or foreign literature in which a pregnant woman was induced because of a dilated fetal renal pelvis or severe hydronephrosis, unless the renal pelvis ruptured, in which case an early cesarean section may be required to deliver the baby and to do the surgery in a timely manner. I have only had one fetus in which hydronephrosis was found at 33 weeks of gestation and the pelvis ruptured at 35 weeks of gestation, in which case the baby had to be delivered early and then operated on. Moreover, even if the renal pelvis ruptures unfortunately, the child is not impossible to have, and with timely and effective treatment, the child can still recover. Our hospital recently treated two children with ruptured renal pelvis, both of whom recovered after surgery. Therefore, I would like to say to all parents that fetal hydronephrosis is not irredeemable. If you find a fetal hydronephrosis, you must consult a pediatric urologist and not give up a new life easily.