Waking up once an hour may be caused by physiological factors, vitamin D deficiency, digestive system diseases and other factors. 1. Physiological factors: such as the presence of noise, indoor temperature is too high or too low, not timely change urine and other physiological factors, can lead to the baby waking up once an hour, but there is no other abnormal performance, eliminating the triggers, may be improved on their own. 2. Lack of vitamin D: when the baby body lacks vitamin D, may affect the absorption of calcium, will lead to the baby in the sleep is not stable, once an hour to wake up, may also be accompanied by more than crying, pillow baldness and other abnormal performance. 3. Digestive system diseases: due to the imperfect development of pediatric digestive system, easy to intestinal spasm and intestinal colic, will cause abdominal pain, abdominal distension and other symptoms, will often wake up in bed. The baby wakes up once an hour, and there are other abnormal manifestations, should be vigilant for disease factors, parents are advised to take their children to the doctor as soon as possible for examination and treatment, to avoid delaying the condition.