The cause of redness and swelling of the newborn’s belly button is due to the fact that the newborn’s immunity is relatively low after birth, which is mainly due to the age of the newborn, who is relatively young and has a low concentration of immunoglobulins and other antibodies, which can cause a weakening of the newborn’s resistance. The parents of the newborn are not taking proper care of the newborn, such as not disinfecting the newborn with iodophor on a regular basis every day, and these factors will lead to an increase in the probability of neonatal umbilicus occurring in the newborn, which will result in redness and swelling of the navel, and even pus flowing from the navel of some newborns. For this situation, you can disinfect the newborn with iodophor or apply topical application of Bactrim to the newborn.