What is the Standard Chart for Infant Head Circumference Development?

The standard head circumference for a three-month-old baby should be approximately 38.2-43.4 cm for boys, with an average of 40.8 cm, and 37.4-42.2 cm for girls, with an average of 39.8 cm. Generally, a baby's head circumference grows about 8 cm in the first half of life after birth, and then 3-4 cm in the second half. After reaching 4 years old, the growth of head circumference slows down significantly, and almost stops after 10 years old. The size of a baby's head circumference can be measured against the standard range mentioned above. If the actual head circumference is more or less than two standard deviations from the normal average, it may be diagnosed as macrocephaly or microcephaly.

A baby's head circumference being smaller than average generally refers to a situation where the baby's head circumference is smaller than the median minus two standard deviations of the head circumference of peers, or even below the third percentile. In this case, the baby's intellectual development may be limited, and they may lag behind in physical strength. Some may even experience convulsions. These babies typically have small and pointed heads with narrow foreheads. If it is determined after measurement that the baby's head circumference is smaller than average, it is advisable to consult a doctor promptly to rule out any underlying diseases. Additionally, if conditions permit, an intelligence test can be conducted to see if there are any intellectual deficits. A comprehensive examination at the hospital can assist in addressing the baby's condition.

A baby's head circumference being larger than average refers to a situation where the measured head circumference is greater than the normal value. This is generally caused by some underlying disease. In clinical practice, the main cause of increased head circumference in children is found to be hydrocephalus. Therefore, if it is discovered that a baby's head circumference is abnormally large, with a noticeably larger head compared to the body, it is recommended to seek medical attention promptly to investigate whether the baby has diseases such as hydrocephalus or brain tumors. Early treatment is essential to minimize the impact on the child.