Infants and toddlers who do not sleep soundly at night may be caused by discomfort in the surrounding environment, vitamin D deficiency, intestinal parasitic infections, and other discomforts such as fever. 1. The surrounding environment is not comfortable: such as indoor temperature is too high or too low, the weather is too dry, around the more noisy, etc., are easy to cause infants and young children sleep at night, need to be adjusted at the appropriate time of clothing, try to create a quiet sleep environment. 2. Vitamin D deficiency: when the child is deficient in vitamin D, it will be easier to wake up, some babies will also be more prone to sweating at night, then we have to consider that the lack of vitamin D caused by the lack of sound sleep. 3. Intestinal parasitic infections: If infants and young children have intestinal parasitic infections, they will also wake up and cry at night due to intestinal discomfort. 4. Others: Babies can also have trouble sleeping when they have other discomforts, such as fever and diarrhea. Infants and children do not sleep soundly at night, there may be other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.