There are many reasons why newborns do not sleep soundly and always cry, including physiological factors such as environmental discomfort, as well as calcium deficiency, upper respiratory tract infections and other diseases caused. 1. Physiological factors: newborns just born, the external environment is not yet adapted, especially the environment is more noisy, light is stronger, resulting in newborns discomfort, so that the phenomenon of crying and sleep is not solid. The central nervous system of the newborn is not well developed after birth, and it is easy to have a startle response, which can also lead to crying and other phenomena. 2. Pathological factors: (1) Calcium deficiency: after the birth of a newborn baby, the calcium content of the body is relatively low, which causes the newborn baby to sleep at night, crying, sweating and other phenomena. (2) Upper respiratory tract infections: mainly caused by viral or bacterial infections, which can lead to fever, cough and runny nose and other uncomfortable symptoms, so it can also cause sleeplessness and crying. Newborns sleep at night, always crying, may also be other reasons, it is best to take the baby to the hospital in a timely manner to avoid adverse consequences.