A day in the incubator is equivalent to a few days in the mother’s body, and it is impossible to compare them in a clinical setting. In the mother’s body, the baby is in a constant temperature and safe environment, the necessary nutrients and oxygen can be obtained through the mother’s body, through the placenta and umbilical cord to the baby’s body, at the same time, the baby is surrounded by warm amniotic fluid and protection. The incubator is merely a constant temperature environment created to mimic the temperature of the mother’s body, and the nutrients and baby’s developmental rate are not able to meet the conditions of the mother’s environment. However, if the baby has an abnormality in the mother’s body, such as an infection or lack of oxygen, the baby needs to be delivered early, at which time the baby must be placed in the incubator to promote the baby’s continued development. When the baby’s vital signs to meet the normal level, can be removed from the incubator into the outside environment for growth and development. Therefore, the baby in the incubator to stay a day can not be compared with the mother to stay a few days, the specific baby out of the incubator time to follow the doctor’s instructions.