An important measure of a child’s health; physical growth follows a similar pattern in most children. With some variation in the first year of life, girls and boys grow at the same rate. Boys are usually slightly larger, except briefly at puberty. The rate of growth is fastest during embryonic and fetal development and remains fast during infancy until it slows at about age 2 or 3. The onset of puberty triggers another dramatic growth period that lasts until full adult height is reached in the late teens. Factors that influence growth usually can be categorized as either environmental or hereditary. Environmental factors may include nutrition and emotional welfare. Genetic traits, ethnicity, and hormones are considered hereditary influences. General health also influences growth. Slowed growth may indicate a number of illnesses or poor nutrition.
As a child develops, there is a noticeable increase in size. This growth is commonly monitored by measuring height, weight, and, in the case of babies, head circumference.
The most rapid period of growth takes place before birth. Subsequently, growth remains swift during the first few years of life, particularly in the initial year, but it gradually slows down during childhood. Another significant phase of growth is marked by puberty, extending until the attainment of adult height and weight, typically occurring around ages 16 to 17 in girls and between 19 and 21 in boys.
During childhood, the body shape undergoes changes due to varying growth rates in different areas. For instance, at birth, the head is already about three-quarters of its adult size, and it nearly reaches full size within the first year. However, as the body continues to grow at a faster pace than the head, it becomes proportionately smaller over time. This discrepancy in growth rates accounts for the changing body proportions during childhood.
Heredity and environmental factors, such as nutrition and overall health, have an impact on growth. Additionally, hormones, including growth hormone, thyroid hormones, and sex hormones during puberty, play a vital role in the growth process.
Conditions like cystic fibrosis, classified as chronic illnesses, can hinder growth in children. Even minor illnesses can temporarily slow down the growth rate, but typically, the rate catches up once the child recovers. Slow growth can sometimes be the sole indicator of a child being ill, malnourished, or emotionally distressed, and this is referred to as “failure to thrive.” However, it’s important to note that short stature alone does not necessarily indicate poor health.
Abnormally rapid growth is a rare occurrence. Typically, it can be attributed to a familial trait, but in some cases, it might indicate an underlying disorder, such as gigantism caused by a pituitary gland tumor.