Jaundice of less than 12.9mg/dl is normal for a 20-day-old full-term newborn. Full-term newborns may have jaundice after birth, the jaundice value may reach the highest level in about 7~14 days, and will gradually subside after that, if the jaundice value of newborns is less than 12.9mg/dl, it is generally normal, and basically it will not have a big effect on the newborn’s physical development. If the jaundice value of the newborn is high after 20 days, we need to be alert to the possibility of pathological jaundice, if pathological jaundice has already appeared, we need to pay attention to it, so as not to cause the jaundice symptoms to worsen, which may endanger the life of the newborn. In normal times, we need to closely monitor the jaundice value of the newborn, and regularly consult the doctor for review, and consult the doctor in time if there is any discomfort.