The growth and development of children is a long-term, continuous process and has its own rules. Growth and development are divided into three stages: 1, infancy (under 2 years old, rapid growth period): the first year after birth, the fastest kidney speed, can grow 25cm, the second year can grow 10cm. mainly by the role of thyroid hormone. 2.Childhood (2 years old – before puberty, growth slowdown period): annual growth of 5-7cm. mainly by growth hormone action. 3.Pubertal period (accelerated growth period): boys can grow 25-28cm, girls can grow 23-25cm, mainly by growth hormone and sex hormone. How can I know if my child’s height is normal or low? Once you know the growth pattern of your child, you can know if your child’s (normal length at birth) height is normal by monitoring the growth rate of your child. In other words, if a child grows less than 7 cm per year from age 1-3, less than 5 cm per year from age 3 to prepubertal, or less than 6 cm per year during puberty, it may indicate that the child has a growth retardation problem. Parents can also keep an eye on the height of children of the same age for comparison. If the child’s height is significantly shorter than that of his or her peers, or if the child was previously at a normal level but has gradually slipped to the lower-middle level, it may indicate that the child has a growth retardation. The problem is that many parents nowadays do not know how many centimeters their child grows in a year? So it is recommended that parents, from the time their child is born, should prepare a special book to measure and record their child’s height regularly. It is recommended that parents measure their child’s height every 3 months and draw a growth curve, and if the growth rate is too slow, they need to seek prompt medical attention.