How fast do babies grow in their first year? Does sleep help babies grow and develop?

Author: Liu Li, Chief Physician, National Children's Medical Center, Beijing Children's Hospital, Capital Medical University

Reviewer: Ma Mingsheng, deputy chief physician, Peking Union Medical College Hospital

0-1 years old is often referred to as infancy. Infancy is the fastest growing period in a child's life.

For example, the average birth weight is 3 kg; at 3 months, the weight can double to 6 kg; at 1 year old, the weight can triple to 9 kg. This is a general rule.

Of course, this is an average value, and there will be some differences for each baby.

Figure 1 Original copyright image, no permission to reprint

For example, height can increase by an average of 25 cm in a year. In the first three months, it increases by 3-4 cm per month, in the third to sixth months, it increases by about 2 cm per month, and in the sixth to twelfth months, it increases by no less than 1.5 cm per month.

Figure 2 Original copyright image, no permission to reprint

Relatively speaking, boys grow faster than girls.

1. My one-year-old baby eats a lot but doesn’t gain weight. What could be going on?

This situation is usually caused by problems with the child's digestion and absorption, or some disease, which results in excessive consumption of nutrients, which can lead to eating but not growing. There are also some rare metabolic diseases or genetic abnormalities that can also cause children to eat but not grow.

Babies who only eat but do not grow are commonly seen in the outpatient clinic. There are children with poor digestion and absorption, and children with food allergies. For example, milk protein allergy and egg allergy will cause the child's overall digestion and absorption function to be poor. These children eat a lot but do not gain much weight.

2. My one-year-old baby grows slowly in height. Is it because of calcium deficiency?

There is such a possibility, because growth mainly involves the growth of long bones. After calcium enters the human body, 99% of it is deposited in the bones. If the baby lacks calcium for a long time, it will definitely affect the growth of height.

But this is only one aspect, because there are some other factors that affect height. For example, babies who are zinc deficient will not grow easily.

There are also children with endocrine abnormalities who are prone to slow height growth. For example, babies with hypothyroidism and pituitary diseases may have a good weight growth but unsatisfactory height growth. So you still need to go to the hospital for a check-up to find out the specific cause.

3. Does sleep help babies’ growth and development?

There is an old saying for babies: "One inch of growth per sleep." This is because during sleep, the body needs to rest, recover many functions, and excrete some waste. On the other hand, in deep sleep, the pituitary gland secretes a large amount of growth hormone, which is very beneficial to the growth and development of the baby.

Therefore, if the baby does not sleep well, it will affect the baby's overall physiological function, the secretion of growth hormone, and will definitely affect the baby's growth and development.