A baby’s physical development is determined by a wide range of factors, including genetics, nutrition, environment, health condition, and activity level. In this regard, there is a recognized discrepancy in what is considered the ‘normal growth pattern of a baby. These discrepancies often make parents worry and wonder if their babies are bigger or smaller than others of the same age. As a way of answering these questions, the baby growth chart was developed.
It is a chart that shows the expected developmental level of babies at different stages of their early lives.
The first baby growth chart was developed in 1977 by the National Center for Health Statistics (NCHS). In 2000, the Centers for Disease Control and Prevention (CDC) provided updated charts. Similarly, the World Health Organization (WHO) shared the international baby growth rate.
NOTE
CDC recommends that parents use WHO charts for children under the age of 2 years and CDC charts for children above 2 years.
Download Free Charts
You can download our free templates that will help you read, understand, and interpret the chart.
WHO charts
The World Health Organization charts are recommended for use by children below two years old. Therefore, these are the charts that you should use from birth to 24 months:
CDC charts
Center for Disease Control and Prevention (CDC) also have growth charts, which are recommended for use by children over 24 months (2 years). These are the CDC growth charts that you should use for children above 24 months:
What Do Growth Charts Measure?
These charts are detailed and capture the essential elements that define the growth of a child. A child’s development is assessed using the charts. Healthcare providers use these when commenting on the overall health of a child.
A growth chart covers the following:
- Head circumference
- Length/height
- Weight of a baby
Birth Weight
The weight of babies differs at birth and as they grow and develop. However, WHO states that the average weight of a newborn is between 7 and 7 ½ pounds (3.2 to 3.4 kg). A baby that is born less than 5 pounds 8 ounces (2.5kg) is considered to have a low birth weight. A child that is born with more than 8 pounds and 13 ounces (4.0 kg) is considered larger than average.
The birth weight of a child is affected by various factors, as highlighted here:
- How many weeks a pregnancy lasts: If a child is born before the completion of the pregnancy (before the due date), its weight will be smaller. Contrarily, a baby born after the due date is likely to be larger. This concept is explained simply by the fact that the baby grows during pregnancy.
- Smoking: Smoking has adverse effects on babies’ health. So, when a pregnant mother smokes during pregnancy, the child is likely to be smaller.
- Gestational diabetes: Diabetes during pregnancy often results in larger babies.
- Nutritional status: The nutrition of the mother during pregnancy directly affects the growth of the baby. Therefore, a mother with poor nutritional tendencies will lead to the birth of a smaller baby, while excessive weight gain is likely to lead to larger babies.
- Family history: Sometimes, family history affects the birth weight. A baby can be born larger or smaller based on family history.
- Gender: Boys tend to be larger than girls. This is purely based on the average data, and it may vary depending on other factors.
- Multiple pregnancies: It is likely for a baby born alone (single baby) to be larger than those born in multiple pregnancies (twins, triplets, quadruplets, etc.)
Weight gain in the first year
After the baby is born, there are expected weight gains to occur. However, these gains are different depending on different babies. However, here are quick weight gain expectations that you can work within the first year of a baby’s life and can track on a growth chart.
The first two weeks
A baby may start losing weight the first few days after birth. This is normal for both breastfed and bottle-fed newborns. On average, a breastfed baby may lose up to 10%, while a bottle-fed one may lose up to 5%.
As the child finishes the first two weeks, most regain their lost weight and weigh nearly the same as their birth weight.
By one month
After a month, a baby has already started developing feeding patterns and is no longer as sleepy as the first few days. These regular feeding patterns developed by infants, combined with their improved sucking power, can lead to an additional pound over birth weight.
By six months
For the first six months, infants gain about one pound every month. Therefore, the average weight (according to the baby weight chart) at six months for boys is 17 pounds, 8 ounces (7.9 kg), and 16 pounds, 2 ounces (7.3 kg) for girls.
By one year
After the sixth month of going to the first year, there is a slow weight gain for most babies. At twelve months, the average weight of a boy is 21 pounds, 3 ounces (9.6 kg), and 19 pounds, 10 ounces (8.9 kg) for girls.
Breastfed infants
Losing weight during the first few days of an infant’s life is quite normal. However, if the baby continues to lose weight or develops poor weight gain signs, then it should signal a problem. If such a child is being breastfed, it could mean that he or she doesn’t get enough breast milk.
Regarding weight gain, breastfed ones don’t gain weight as fast as formula-fed babies. Breastfeeding reduces excessive weight gain and can also prevent obesity.
However, it is also possible for a breastfed child to gain much weight if there is a constant supply of breast milk from the mother or if the child starts to intake solid foods early.
Baby Length/Height
Another aspect of a child’s growth is height: On average, a baby grows by about an inch per month for the first six months. This will reduce by about half an inch after six months.
On average, a six-month-old boy measures 26 ½ inches (76.6 cm), while a girl measures 25 ¾ inches (65.7 cm). At one year, the expected average height of a baby boy is 29 ¾ inches (75.7 cm), while girls record an average of 29 inches (74 cm).
The length or height of a baby is determined by a set of factors that have either direct or indirect influence on how tall they will grow:
- Genetics: The most significant factor that determines the height of a baby is the height of the mother, father, and other family members. The child is likely to get his or her height from within the family.
- Gender: Boys are likely to be taller than girls.
- Nutrition: Nutrition starts right from pregnancy, where the mother is expected to partake of proteins, vitamins, and minerals that will boost the health of the baby’s bones for optimal growth.
- Sleep pattern: Studies have revealed that infants gain height after periods of sleeping.
- Physical activity: The muscles and bones of an infant are built well when the infant is engaged in body movement and physical activities.
- Overall health: The health of a baby is important in determining his or her height. If a child has a chronic illness during childhood, then physical growth can be affected, thus leading to slow height growth.
This chart highlights the tracking of a child’s growth in height. The average is based on the good health of a child from birth to one year.
Age | Height of Boys | Height of Girls |
1 Month | 21 1/2 inches (54.7 cm) | 21 inches (53. 7 cm) |
2 Months | 23 inches (58.4 cm) | 22 1/2 inches (57.1 cm) |
3 Months | 24 1/4 inches (61.4 cm) | 23 1/2 inches (59.8 cm) |
4 Months | 25 1/4 inches (63.9 cm) | 24 1/2 inches (62.1 cm) |
5 Months | 26 inches (65.9 cm) | 25 1/4 inches (64.0 cm) |
6 Months | 26 1/2 inches (67.6 cm) | 25 3/4 inches (65.7 cm) |
7 Months | 27 1/4 inches (69.2 cm) | 26 1/2 inches (67.3 cm) |
8 Months | 27 3/4 inches (70.6 cm) | 27 inches (68.7 cm) |
9 Months | 28 1/4 inches (72.0 cm) | 27 1/2 inches (70.1 cm) |
10 Months | 28 3/4 inches (73.3 cm) | 28 inches (71.5 cm) |
11 Months | 29 1/4 inches (74.5 cm) | 28 1/2 inches (72.8 cm) |
12 Months | 29 3/4 inches (75.7 cm) | 29 inches (74.0 cm) |
note
All inches are rounded to the nearest quarter of an inch.
How to Read the Growth Charts
When you visit your healthcare provider, you will be guided on how to understand the growth of your child. Here is a quick look into the process of reading growth charts. We will explore the four growth charts that you will be presented with when visiting your healthcare provider.
Head circumference chart
The head circumference chart has the X-axis (the horizontal line) and the Y-axis (the vertical line). In the chart, the X-axis represents the number of months, and the Y-axis has the variable that you are measuring, which in this case is the head circumference measurements.
All you have to do is follow the X-axis and Y-axis until they intersect. They will likely intersect at a curved line, which you should follow up to the end and you will be able to see the percentile.
In the example provided above for a 3-year-old girl, the head circumference is 15.5 inches. Following the curved line, it is clear that the child falls in the 50th percentile, which means that half of all 3-year-old girls have smaller heads while the remaining half have bigger heads.
Weight-for-length chart
At the bottom of the grid (X-axis), you can find the length of your child in centimeters or inches. Your child’s weight can be found on the left side of the grid (Y-axis). After you have located the two, you should follow the Y-axis and X-axis until they meet the growth curve, which you should follow to the end to find the percentile in which your baby is.
Check out this chart for a boy’s weight-for-length:
In this example, the boy weighs 10 pounds and has a height of 21 inches. The boy lies in the 90th percentile, which means that 90 percent of boys with this length (21 inches) weigh less than 10 pounds, and 10 percent weigh more than 10 pounds.
Length-for-age chart
The X-axis shows the age of the child and the Y-axis shows the length of the child. You need to locate your child’s age and length on the horizontal and vertical lines up to the point where they will intersect. The intersection occurs on a growth curve, which you should follow to the end.
Check out this example of a girl’s length-for-age chart:
In this example, the child is 18 months old and is 30.5 inches long. She falls in the 10th percentile, which means that 10 percent of girls who are 18 months are shorter and 90 percent of girls of her age are longer.
Weight-for-age chart
The right side of the chart has the baby’s weight (in pounds or kilograms) and the age is on top of the chart (in months). You follow the horizontal lines (Y-axis) and the vertical lines (X-axis) until they intersect. They will intersect in the growth curve, which you should follow to the end to find the baby’s percentile.
Check out the example of a growth chart for a boy’s weight-for-age chart.
In the example provided, the child is a 12-month-old boy who weighs 23 pounds. The boy falls in the 75th percentile, which means that 75 percent of boys of his age weigh less while 25 percent of boys of his age weigh more.
Interpreting the Results
Instead of busying yourself with the actual measurements provided during clinic visits, you should be more concerned with the patterns and consistency indicated on the growth charts. If a baby is growing in proportion, there are no red flags; however, you should be concerned if there is a noticeable change in measurement.
EXAMPLE
You should not be worried if your baby has a lower length and weight, as it could mean that the genetic predisposition is to be skinny and short. However, if the weight percentile changes from, let’s say, the 80th to the 25th percentile, then there could be a problem with eating, which you should be concerned about.
One thing that you need to know when interpreting the results is that babies grow at different paces. Therefore, it is perfectly normal to be along with the measurements of the 15th or even 99th percentile. Your only concern should be rapid or extremely noticeable changes.
Percentiles Overview
Percentiles are important in growth charts as they show how your child is compared to other children of the same gender and age. Percentiles are represented in them as curved lines.
EXAMPLE
If your baby lies in the 70th percentile for length-for-age, it means that 70 percent of children of the same gender and age are shorter while 30 percent are longer.
This, in itself, doesn’t provide a complete picture, and your healthcare provider may look into other factors that affect the growth of your child as compared to the average growth curve as indicated in the chart.
While looking at the percentiles, you should not put much focus on the numbers but on other factors that influence a baby’s growth, such as genetics, nutrition, activity levels, environmental factors, and health problems. The growth spurts of babies are different depending on these factors.
Change in Baby’s Growth Pattern
A change in a baby’s growth pattern does not necessarily show that there is a problem. Sometimes, it could just be that your child is experiencing a growth spurt. However, if you notice a noticeable change in the growth pattern, you should engage your healthcare provider to investigate further.
EXAMPLE
If your child has been heavier than 40% of other children of the same gender and age, and then he/she suddenly becomes heavier than 80% of children of his/her age and gender, then the pediatrician should investigate this.
Another change that you need to be concerned about is if your child is not steadily gaining height and weight.
Below or above-average babies
So, you are probably worried if your baby is below or above average for the growth patterns of other babies of his or her age. A majority of children fall within the 3rd and 97th percentiles. If the child doesn’t fall into this category, there could be a lot of factors that the doctor will be looking into.
EXAMPLE
Genetics could play a role in the concern for a child being below or above average. This is because some families have inherent genes for fast growth, while others have genes for slow growth.
As a parent, you should try not to worry a lot but discuss the concerns with your baby’s doctor to determine the right course of action, if there should be any.
The chart can be tiresome for most parents. As a parent, avoid direct comparisons between your child and other children and focus on the growth of your child as an individual. If you focus on your child, you will be surprised to see the milestones your child has made that the chart cannot show you because of comparison with other children.
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Final Words
With all the information shared here, you do not have to worry about your child anymore. You can now comfortably understand the growth patterns of your child using the growth charts provided.