It is usually abnormal for a newborn not to urinate for a day, which may be physiological, such as low breastfeeding and more sweating; or pathological, such as fever, vomiting, diarrhea, or even urinary system diseases. In the first 2 days after birth, the newborn should urinate at least 1~2 times a day, and from the 3rd day after birth, the urination should be up to 6~8 times every 24 hours. If the newborn has less feeding and more sweating in the first 1~2 days after birth, there may be temporary oliguria, and as the newborn eats more, the urine output will gradually increase. If the newborn has fever, vomiting, diarrhea and other symptoms, it may lead to dehydration, then the symptoms of anuria and oliguria will occur. In addition, certain diseases of the urinary system, such as abnormal development of the urinary system, congenital renal malformation, etc., may also lead to newborns with oliguria and anuria. It is recommended that parents should take their newborns to the hospital in time to clarify the cause of the disease under the guidance of the doctor and treat it in time.