For a three-month-old child, the diagnosis of cerebral palsy is not straightforward and its confirmation needs to be made around one year of age. If, at around one year of age, there is still a relatively obvious delay in the development of motor function, accompanied by relatively obvious abnormalities in muscle tone and posture, the possibility of cerebral palsy can be considered. In order to avoid expanding the diagnosis of cerebral palsy, children within one year of age are not directly diagnosed with cerebral palsy, however, it does not mean that there are no symptoms within one year of age, children within one year of age can also have developmental problems. At around three months of age, the child may have a tendency to lag behind in development, such as not being able to hold his head up on his stomach, eat his hands well, not be able to smile or laugh audibly, and may not be able to be held vertically. When this happens, it is important to consider that there may be developmental problems, but it is not absolute. In addition, a muscle tone test can be performed at around three months of age to detect early abnormalities in muscle tone, especially if there is an increase in muscle tone.