There is no fixed standard for the growth and development of infants, which is generally evaluated through the pattern of physical development such as weight, height and head circumference.
1. Weight: The weight of a full-term infant at 3 months of age is generally one times higher than that at birth, usually around 6 kilograms, or calculated using the formula [age (months) + 9]/2.
2. Height: The height of a full-term infant at 3 months of age is usually 11~13cm higher than the height at birth, usually at 60~63cm, which is affected by genetic, endocrine and other factors.
3. Head circumference: the head circumference of a full-term infant at 3 months of age will generally increase by 6cm compared with that at birth, and the average head circumference at birth is 33~34, so the head circumference of a 3-month-old infant is 39~40cm.
The evaluation criteria of infant development at 3 months also include chest circumference, upper arm circumference, subcutaneous fat, body proportion and proportionality. It is recommended to go to a pediatric care unit for a professional evaluation to get an accurate picture of your child’s growth and development.