Infants who do not sleep at night are considered to be caused by too much sleep during the day, environmental factors, lack of vitamin D and calcium, indigestion and so on. 1. Excessive daytime sleep: If the infant sleeps more during the day, he/she will be more energetic at night. 2. Environmental factors: It may be that the environment in which the infant sleeps is too noisy or the light in the room is too bright, which will affect the infant’s sleep and cause the infant to stay awake at night. 3. Lack of vitamin D and calcium: If infants lack vitamin D or calcium, it will easily lead to increased neuromuscular excitability and cerebral cortex excitability, which will affect the night sleep, and will also be accompanied by excessive sweating, occipital baldness and other symptoms. 4. Indigestion: Most of them are caused by improper feeding, such as overfeeding, which can easily cause indigestion, and the baby feels abdominal discomfort, such as bloating and abdominal pain, which affects sleep. If the baby does not sleep at night and is accompanied by symptoms of discomfort, such as crying, slow growth, etc., you should go to the hospital to find out the cause.