Babies with fever sleep with a startle, or infantile jumping, is usually caused by high body temperatures, underdevelopment of the child’s nervous system, or a calcium deficiency. As the baby is too young, the development of the nervous system is not perfect, in the fever, the central nervous system may be affected to a certain extent, resulting in a significant increase in the excitability of nerve cells leading to abnormal discharge, which leads to the baby’s fever sleep jump. In addition, due to the baby’s growth and development is relatively fast, the amount of calcium required is larger, so it may cause calcium deficiency in the body of the state, and the lack of calcium when the neuromuscular excitability will also increase significantly. At this time, if the baby has a fever, it will also lead to the phenomenon of jumping. Once found that the baby fever symptoms appear a jump, need to consult a doctor in time, check the cause of the disease, and take targeted treatment to avoid adverse effects.