4D ultrasound is a normal result if it shows that both kidneys of the fetus are visible. 4D ultrasound is referred to as a gross examination, which can clarify whether the fetus has any abnormal development of internal organs. Normal people have two kidneys, so if 4D ultrasound for fetal examination can see two kidneys completely normal, do not need to worry too much. If there is a congenital developmental abnormality, it may lead to the absence of one side of the kidneys, or one side of the kidneys is significantly reduced in size. If the fetus has abnormal development of the urinary system, it may lead to the situation of obvious separation of the renal pelvis, and when there is an abnormality in the 4D ultrasound, it is necessary to go to the antenatal clinic in time for consultation.