Three-month-old babies can’t lift their heads up may be caused by physiological factors, which is normal; however, it may also be caused by pathological factors, such as calcium deficiency, cerebral palsy, etc., which is abnormal. 1. Physiological factors: If parents usually do not train the baby’s neck strength, then there may be three-month-old baby can not lift his head, which is a normal phenomenon, it is recommended that parents usually encourage the baby to lift his head and strengthen the strength of his neck. 2. Calcium deficiency: If the baby’s bone growth and development is affected by insufficient calcium intake, and then the phenomenon of not lifting the head, parents can give the baby vitamin D drops and other drugs under the guidance of the doctor, and at the same time, can take the baby to sunbathe more. 3. Cerebral palsy: It may be related to neonatal stroke, brain development malformation, etc. Affected children show backwardness in motor development milestones, such as lifting the head, sitting, standing, etc. Parents are advised to bring their children to the hospital as soon as possible. Parents are advised to bring their children to the hospital as early as possible and do some functional training under the guidance of the doctor, such as physical exercise training, etc. Surgery is required for severe cases. If your baby is unable to lift his/her head at three months, parents are advised to take your baby to the hospital to find out the cause in time to avoid delay in treatment.