How long does it take for a newborn's blood oxygen level of 85%-90% to return to normal?

　　Blood oxygen refers to blood oxygen saturation. Under normal circumstances, the recovery time for neonatal blood oxygen saturation at 85%-90% varies depending on the medical condition and may require 3-7 days, mainly depending on the specific condition of the newborn's illness. Parents should promptly take the newborn to the hospital for treatment. The analysis is as follows:

　　1. 3-5 days: Neonatal blood oxygen saturation at 85%-90% may be caused by pneumonia. In some newborns, the condition is mild, presenting only slight tachycardia and increased respiratory rate. With timely treatment such as oxygen inhalation to improve hypoxia, the condition may be controlled quickly. At this time, the recovery time may be relatively short, requiring 3-5 days.

　　2. 5-7 days: However, some newborns have poor physical conditions. If the illness is severe and obvious discomfort symptoms appear, such as significant tachycardia, decreased blood pressure, cyanosis of the lips, long-term hypoxia may cause varying degrees of brain damage. At this time, it may also be necessary to use a ventilator for assisted breathing and even anti-infective treatment. The recovery time may be relatively long, generally requiring 5-7 days.

　　During the treatment period, parents should enhance the care of the newborn, maintain suitable room temperature and humidity, strengthen warmth and feeding to promote the newborn's recovery.