The baby’s arms are always backward when holding may be a normal physiological phenomenon, may also be calcium deficiency, poor development of the nervous system and other reasons. 1. Normal physiological phenomenon: the baby’s arms are always backward when holding, may be due to the baby’s central nervous system is not yet fully developed, this is a normal physiological phenomenon, do not need to worry too much. 2. Calcium deficiency: when a baby is deficient in calcium, due to the lowering of blood calcium, it is easy to affect the neuromuscular function, resulting in muscle spasms, which may be manifested in the case of the baby’s arms are always backward when holding. 3. poor neurological development: baby ischemic hypoxic encephalopathy, intracranial infection, bilirubin encephalopathy, etc., can make the baby’s nervous system damage, the normal development of nerve cells is limited, which leads to the baby’s high muscle tone, there may be a baby arms always backward when holding the symptoms. If your baby’s arms are always backward when you hold them, you need to go to the regular hospital in time to do the relevant examination and treatment.