The main mechanisms regulating growth differ at different stages of life, and growth patterns are divided into intrauterine and postnatal growth according to the regulatory mechanisms. Postnatal growth is further divided into infancy, childhood, and adolescence. The following is mainly about postnatal growth.
1, infant growth: generally position the time after birth to 2 years. During this period, the growth rate of physical growth is at its peak, 25cm in the first year after ascension, 10cm in the second year; by the age of 2 years, the weight growth is 4 times that of the birth. 2 years after the growth rate gradually declined. Its growth regulation mode is mainly nutritional, pro-growth axis regulation and genetic influence from the age of 1 year to 2 years after the full emergence, that is, the growth and development within 2 years of age is mainly nutritional influence.
2, childhood growth: the time from 2 years old to the beginning of puberty before. The growth rate decreases and remains relatively stable at 5-7 cm per year. However, the growth rate is not continuously homogeneous and can fluctuate rapidly or slowly, and the rate can fluctuate within a year. Therefore, it should be dynamically observed for at least 6 months to compare the normal judgment of growth rate. The growth during this period is mainly regulated by the growth promoting axis and can be influenced by genetics, nutrition, heart, etc.
3, pubertal growth: after the initiation of pubertal development, growth enters the second post-life peak, characterized by rapid growth in height. It can also be considered as divided into three stages.