What does renal pelvis separation mean? Separation of renal pelvis refers to the separation of the renal pelvis of the embryo or fetus. There will be two screening tests for fetal anomalies at 21-28 weeks of pregnancy, and the screening tests for fetal anomalies will routinely check the condition of each organ. When the kidneys are examined, attention will be paid to whether the renal pelvis is separated or not. The so-called renal pelvis is separated to a certain extent, which is called hydronephrosis, and some fetuses have congenital anomalies, and hydronephrosis will occur. The renal pelvis is used to store urine, which is discharged through the renal pelvis to the ureter, which is then transported to the bladder, and from the bladder to the urethra, from which it is discharged out of the body, and any malformation of this pathway, no matter which part of the body is malformed, may lead to the upstream renal pelvis to develop hydronephrosis. For example, if there is ureteral stenosis, congenital ureteral stenosis, the urine can not be drained out of the ureter and bladder, and it will accumulate in the renal pelvis area, resulting in hydronephrosis. If the separation of the renal pelvis is less than 1cm, it can actually be observed, sometimes the child may hold a urine in the uterus will cause the separation of the renal pelvis, it does not matter, you can review after two weeks, if it is greater than 1.5cm should be especially concerned, there may be fetal hydronephrosis.