Ultrasound can reveal fetal urinary problems. Usually, the 4D ultrasound can be used to conduct a malformation examination when the fetus is about 5-6 months old, at which time the development of the urinary system can be detected. In addition, there will be a detailed ultrasound examination as a supplement to the malformation examination when the fetus is 7-8 months old, and at this time, the urinary system can be examined as well. Problems with the urinary system of the fetus are usually caused by pathogenic bacterial infections or genetic abnormalities during pregnancy. If the examination reveals that the condition of the fetus is abnormal, then it is recommended that several more examinations be performed to confirm whether there is a real problem or not, and if the problem with the urinary system of the fetus is serious, it is recommended that the pregnant woman receives professional medical advice.