It is normal to find no separation of the bilateral renal pelvis during pregnancy, especially during fetal ultrasound. If the fetal ultrasound during pregnancy reveals that the bilateral renal pelvis is separated, it indicates that hydronephrosis is present, and this kind of hydronephrosis needs to be actively searched for the cause, and whether or not it affects the development of the fetus will be judged according to the specific situation. As for the title, it is a normal phenomenon that the bilateral renal pelvis of the fetus is not separated, so there is no need to care about it. If there are other abnormalities, we should actively seek help from obstetrics, urology and nephrology. Therefore, fetal bilateral renal pelvis without separation is normal for the same reason as bilateral non-separation found in normal people who have a urologic ultrasound. Unless bilateral non-separation is present with other abnormal reflections and other abnormal imaging suggestive of a lesion, a lesion may be considered. If there are no hints, bilateral renal pelvic nondetachment is normal.