The umbilical cord of newborn babies usually falls off in 3-7 days. The umbilical cord of newborn babies has been detached from the placenta, and due to local ischemia, it will become hard and black, and most of the umbilical cord of newborn babies will be detached slowly after 3-7 days. After the umbilical cord is detached from the placenta, the local tissues will have scabs, and sometimes there may be infections such as redness, swelling and even pus around the umbilical cord, which need to be disinfected by wiping with iodine swabs. After the umbilical cord falls off, newborn babies need to be actively cared for and the growth of the navel should be observed, if the local infection continues to worsen or the navel tissue gradually protrudes, it is best to consult a doctor for examination in a timely manner.