Once your child is born, the one thing every parent is first concerned about is their baby’s rate of growth. Pediatricians use a growth chart comparing a child’s height and weight statistics to other children, creating a percentile number for each figure. For example, if your child is on the 60th percentile for weight and 40th percentile for height, it means that he or she weighs more than 60% of other children their age and is taller than 40% of other children.
Throughout the infant stage and their childhood, parents may find themselves comparing their child’s rate of growth to other children around them. They may also become obsessed with percentile numbers and believe it’s an indication of whether their child’s growth pattern is healthy. But the numbers in these charts are just a benchmark. It’s normal for your child to be bigger or smaller than the average child, said Stephanie Kirkconnell, M.D., a pediatrician at Alliance Pediatrics.
“From infant to age 1, as a pediatrician, we are really looking for consistent weight gain,” Kirkconnell said. “A newborn’s size at first is really a reflection of the intrauterine environment. After that, a baby’s growth is influenced by genetics and nutritional status. Every child’s trajectory is different, so as long as your pediatrician feels your baby is growing at a healthy rate, there is no reason to be concerned.”
According to the World Health Organization, the average baby born in the United States weighs about 7 pounds, and 3 ounces. The average baby girl’s birth weight (7 pounds, 1 ounce) is a bit smaller than the average baby boy (7 pounds, 4 ounces). As for height, the average newborn is 19 1/2 inches long, with girls measuring 19 inches and boys measuring 19 3/4 inches.
A growth spurt is a period where the child grows faster on average than in other periods of his or her life. Growth spurts occur most frequently in the first year of life when a child grows the most they will throughout their childhood. Nemours Children’s Specialty Care advises that while babies can have growth spurts at any time, they typically will have their first growth spurt between one and three weeks; and another between six and eight weeks. Typically, they will occur again at three months, six months and nine months. After the first year, on average, babies will triple their birth weight and grow an average of 10 centimeters.
What determines growth patterns?
Different factors affect a child’s growth pattern with the most major cause being genetics. However, there are other factors that may be in play. Breast fed babies may grow more rapidly in the first three months than formula-fed babies with the opposite being true after that time. Hormonal imbalances, medications like steroids, health conditions and genetic disorders may affect growth. Finally, good sleep helps to influence growth positively.
After babies turn 1, growth rate slows considerably. After age 4, they grow about 5-6 centimeters per year until puberty, which is the next big growth spurt and signals the onset of puberty. There is a wide range of ages when children may start puberty. It also differs between genders as well. Girls will typically begin puberty between the ages of 8 and 13 and have their major growth spurt between the ages of 10 and 14. Boys will boys start developing between the ages of 10 and 13 and have their major growth spurt between 12 and 15.
Kirkconnell advises parents to understand that this range of ages for puberty varies widely between all children. Many children who are “late bloomers” have constitutional growth delay. This is a normal condition that affects children growing at a healthy rate, but who may not experience puberty at the “average” time, she said.
“Constitutional growth delay occurs when children have a delayed bone age. They are still growing and developing normally, but they may reach puberty later than their peers. Typically, one or both of their parents likely had a constitutional growth delay as well. They will eventually develop and catch up to their peers later in life,” Kirkconnell said.
As far as physical growth, girls typically stop growing at about age 15 and boys stop at around age 17, Kirkconnell said.
A pediatrician will look at their current height and weight trajectory and address any areas of concern. Eating a healthy diet, getting adequate sleep and being physically active are all good habits to keep to encourage healthy growth in every child.
AVERAGE WEIGHT AND HEIGHT FOR EACH STAGE
According to the World Health Organization and the U.S. Centers for Disease Control and Prevention.