8-month-old baby is prone to crying at night during sleep for the following three common reasons: First, the baby is too tired to play during the day, the baby may not nap during the day, play before sleep is more tired, more excited, this situation can easily cause the baby to cry at night during sleep. Second, the child’s sleep environment is uncomfortable, such as too hot or too dry, can cause the child uncomfortable, causing sleep is not solid, crying. Calcium deficiency can cause children to wake up easily at night, be irritable, cry easily, sweating and pillow baldness. This situation needs to be treated with oral vitamin AD and calcium supplements, and when the weather is good, take your baby out in the sun. All of the above are physiological states, and babies crying can generally be soothed, but children who cry particularly violently and cannot be soothed need to go to the hospital in time to rule out pathological states.