What is the normal height for a nine-year-old?

The child's body is something that parents pay special attention to, especially the child's height which has a great impact on their whole life. The child's height grows in stages, so it is very necessary for parents to understand the growth standard of their child's height. For example, what is the normal height of a nine-year-old child? This is a question that confuses parents. Let's take a look at a brief introduction below.

According to the standard height formula, a normal nine-year-old child should be 138 cm tall.

Based on the results of the children's physical development survey, the Department of Women and Social Affairs of the Ministry of Health organized relevant experts to research and formulate the "Reference Standards for Growth and Development of Children Under 7 Years Old in China". This standard was officially announced by the Ministry of Health on June 2, 2009. Height and weight are important indicators to measure whether a child's growth and development is normal. The standard calculation formula for normal height and weight of children is introduced as follows: Weight (kg) at 1-6 months = birth weight (or 3 kg) + age in months × 0.6 (kg); Weight (kg) at 7-12 months = birth weight (or 3 kg) + age in months × 0.5 (kg); Weight (kg) at 2-10 years old = age × 2 + 7 (or 8).

The average height of a full-term baby is 50 cm. It grows about 25 cm in the first year after birth, so it is about 75 cm at one year old. Thereafter, it grows an average of 5 cm each year. Therefore, the height of a child from 2 to 12 years old (cm) = age × 5 + 75 (cm). Anyone whose height exceeds the standard by 10% or is less than 10% is considered abnormal.

What factors affect a child's height?

1. Nutrition: Height is the sum of the head, spine and lower limbs. It is an important indicator of bone growth, especially long bone growth. When the baby's nutrition cannot meet the needs of bone growth, the rate of height growth will slow down. Nutrients closely related to bone growth include vitamin D, calcium and phosphorus. Insufficient iodine and zinc can also cause babies to be short.

2. Sleep: The growth hormone secreted by the pituitary gland is an important hormone that stimulates the baby's growth. The secretion of human growth hormone is unbalanced within 24 hours a day, and its secretion is higher during sleep than when awake. Lack of sleep will affect the baby's growth. Generally, newborns require 20 hours of sleep per day and night. From 2 to 6 months, it is 15 to 18 hours; from 6 to 18 months, it is 13 to 15 hours; from 18 months to 3 years old, it is 12 to 13 hours; from 3 to 7 years old, it is 11 to 12 hours. The amount of sleep a baby needs each day varies greatly from person to person. If some babies sleep less but their spirit, mood, and growth and development are normal, there is no need to force it.

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