The baby sleep legs hit the bed, may be a normal physiological phenomenon, but also may be related to calcium and vitamin D deficiency and other disease factors. 1. Physiological phenomenon: for most babies, most of them are normal to raise their legs and hit the bed when they sleep. For example, when the baby is sleeping, the ambient temperature may be too high, the bedding is too thick, etc., so the baby will change the position to continue to sleep, when changing the position, there may be the phenomenon of lifting the legs and hitting the bed. 2. Calcium and vitamin D deficiency: some babies sleep legs smashed bed, accompanied by increased sweating and crying and other phenomena, need to be highly suspected and the body of calcium and vitamin D deficiency, so it will cause the baby sympathetic nerve excitation, easy to cause sleep is not stable or raise the legs smashed bed and other phenomena at first glance. The baby sleep legs hit the bed, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.