Two and a half months of infants still can not raise their heads may be normal, may also be pathological reasons, need to be based on the baby’s comprehensive situation to determine the specific. 1. Physiological phenomenon, due to the lack of exercise, the baby’s head is too large and other factors lead to poor baby head up, the baby’s muscle strength and muscle tone are normal, through the head up training, can be improved. 2. Pathological causes: calcium deficiency, nutritional vitamin D deficiency rickets children can appear poor head up, the child is also accompanied by cranial softening, night terrors, excessive sweating and other symptoms; cerebral palsy, cerebral palsy children are often accompanied by motor, speech and other developmental delays; malnutrition, malnutrition, malnourished children are often developmental delays, but also manifested in the height, weight does not increase and other symptoms. A two-and-a-half-month-old baby who can’t hold his head up is recommended to be closely monitored and to seek medical attention if necessary.