In the vast majority of full-term newborns, the normal range of heart rate is between 120-140 beats per minute. If a newborn’s heart rate falls within this range, it is a normal physiologic phenomenon. If a newborn’s heart rate is significantly lower than this, it is often due to sinus bradycardia, preterm labor, or even hypoxia. If the newborn baby’s heart rate is obviously too fast, it is often due to heart failure or hypoxia caused by reflex acceleration, and if the newborn baby has fever, it can also cause the heart rate to be too fast. Therefore, if the newborn baby’s heart rate is less than 120 beats per minute or more than 140 beats per minute, it is necessary to promptly find out the specific causes of the abnormal heart rate, so as to target treatment.