Babies always cry suddenly in the middle of the night for the following reasons: 1. Because the nervous system is not well developed, it is easy to be frightened by various factors. When frightened, usually will be manifested as a sudden awakening at night, crying and other performance, this situation can be given a frightened wind san oral, at the same time can be given to bedtime back spinal points of chiropractic treatment for fright, after the fright improved, the child suddenly woke up in the middle of the night symptoms can be improved. 2, due to the baby lack of vitamin D and calcium deficiency, lack of vitamin D will cause plant nerve dysfunction, while vitamin D deficiency will affect the absorption of calcium, there will be a lack of calcium performance. D deficiency will affect the absorption of calcium, there will be a lack of calcium performance, this situation will also lead to the baby sleep in the middle of the night always suddenly cry situation. Vitamin D and calcium supplements can be given symptomatically and the symptoms can be improved.