It is extremely rare for a two and a half month old baby to roll over, of course there are exceptions, but attention should be paid to whether it is caused by pathologic factors, such as asymmetric twisting of the body, which leads to unconscious and uncontrolled rolling over, and it should be combined with the presence of high-risk factors in the perinatal period, such as prematurity, low birth weight, hypoxic-ischemic encephalopathy, kernicterus, and so on. If there is any of the above manifestations and medical history, it is important to visit the hospital in time to detect the abnormality and provide timely intervention, because if asymmetric torsion of the body occurs at this age, it may be a manifestation of brain injury, and it is necessary to visit the hospital in time to perform a cranial nuclear magnetic resonance imaging as well as assessment of motor development.