Trembling of hands and feet when a newborn baby sleeps may be due to imperfect development, or due to vitamin D or calcium deficiency, or due to epilepsy. 1. Imperfect development: if the baby’s hands and feet tremble while sleeping, it may be related to imperfect physiological development. Due to the baby’s young age, the development of the central nervous system of the brain is not yet very perfect, the ability to inhibit the shaking of the limbs is relatively weak, so there will be a trembling of the hands and feet during sleep. As the age increases, it will be significantly relieved. 2. lack of vitamin D, calcium: baby sleep trembling may be lack of vitamin D, calcium, nerve excitability increased performance. 3. Epilepsy: baby sleep trembling may also be caused by epilepsy. There may be other reasons why a newborn baby’s hands and feet tremble when he sleeps, so it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.