Infant Growth Chart
An infant growth chart is used to measure and monitor a baby’s growth.
It is different from the ones used for boys and girls that are past infancy.
There are separate growth charts for measuring a baby’s height, head circumference and weight.
If you live in the United States, there are two kinds of infant growth charts.
The World Health Organization (WHO) has its own baby growth chart which uses basis data from children in Davis, California (USA); Oslo, Norway; Pelotas, Brazil; India; Ghana; and Muscat, Oman.
The second baby growth chart was made by the Centers for Disease Control (CDC) which based its data on measurements taken from children in different age groups.
While the WHO collected data in the periods between 1997 and 2003, the CDC did so in various year groups: 1971 to 1974, 1976 to 1980, and 1988 to 1994.
It was determined and suggested that parents and pediatricians use the growth curves created by the World Health Organization.
At present, the WHO growth standards are used for infants in the United States until two years of age, while the CDC growth charts are intended for U.S. children aged two and older.
It is essential to remember that growth charts are not intended to test how a baby grows or as an individual diagnostic instrument, but to monitor growth and use this data to form a clinical opinion of the baby’s development.
Infants have individual growth rates, so the case for one may not be the same for others.
Additionally, infant boys have different growth patterns and separate charts from infant girls.
What Does An Infant Growth Chart Measure?
While it was previously mentioned that infant growth charts measure height, weight and head circumference, there is a more detailed way of describing what they do.
More specifically, these charts are used for monitoring and assessing babies’ heights, weights and head circumferences in comparison with those of other babies in the same age group.
A pediatrician determines the various measurements and their relationships to each set of data.
A doctor will usually determine an average for each of the abovementioned factors based on what is a normal rate for the age of the infant.
The chart for babies is different from those used for young boys and girls, and it uses percentile lines that run parallel to each other.
The most important thing to remember is that these percentile lines determine the rate of an infant’s growth and their progression or development.
If a baby’s growth is in line with or similar to the chart’s percentile line, the growth rate is normal.
Using An Infant Growth Chart
A pediatrician uses an infant growth chart for the first time after you give birth.
The doctor will measure your baby’s height, weight and head circumference and write the details on the chart.
After this, measurements will be taken regularly when you bring your baby for a visit.
The infant’s weight is the first measurement to be taken followed by the height and the head circumference.
Before taking the weight, the pediatrician will ask you to remove your baby’s clothes. Then, the child will be put on an infant scale.
When measuring a baby’s height, the doctor will lie the child back down before getting the measurement details.
The baby’s legs should be stretched so the pediatrician can properly measure the infant’s height.
The head circumference is taken with the help of measuring tape that is wrapped around the baby’s head from the back to the eyebrows.
Tracking Your Baby’s Growth
As mentioned earlier, the World Health Organization and the Centers for Disease Control each have growth standards.
Doctors use these to calculate the details indicated in growth charts. In addition, the charts are based on the fact that not all infants are the same size and shape.
The percentiles in the charts allow for variation.
To determine what these percentiles mean, the pediatrician looks at the line in which your baby’s measurements exist and uses this information to compare the height, weight and head circumference with those of other babies who are the same age.
For example, if the chart shows your baby’s height in the 45% percentile line, this means that 44% of babies of the same age as your infant are shorter, while 55% are taller.
If a child is in the 95% percentile for weight measurement, it means that 94% of babies of the same age have a lighter weight. The remaining 4% of children are heavier than your baby.
The baby’s height percentile does not necessarily match the weight percentile.
These two can fall on different lines.
Keep in mind that the percentile used in infant growth charts is not similar to the charts used in school.
The chart will provide an indication of whether your infant is growing at a normal rate or not.
This does not mean you should only look at the numbers.
Pay attention to the curves which should be advancing or increasing at all times.
If there is a regular increase in the curve, it is good news because your baby is progressing.
If there is a significant drop or rise in your baby’s percentile lines, particularly over 2 percent, speak to a medical professional for advice.
They will help inform the reason for the change and what steps to take moving forward.
It is also important to consider several factors in determining the proper development of your infant.
Good muscle tone, healthy skin color and regular bowel movements are all positive signs that your baby is growing normally.
It does not matter if your baby is bigger, smaller, heavier or lighter than other babies of the same age.
Most important is a steady development in the chart (again or several gains for every visit to the doctor).
To read the details in the chart, use the following instructions:
- For the weight, look at the right side of the grid, and identify the weight of your baby. Then locate your baby’s age found at the top. Follow the mix of horizontal and vertical lines to the point where these numbers intersect. This curved line will lead you to the percentiles, so follow where it goes.
- For the height, follow the same process you did for the weight, but focus on the left side of the grid. Your baby’s age is indicated at the bottom part of this chart. Follow the lines until you see the growth curve where they intersect. At the end, you will find the weight percentiles.
- For details of the head circumference, focus on the top part of the chart, and look for your baby’s age (in months). A vertical line represents the months. Go to the left side of the grid to find the head circumference. Follow the lines until you see the intersection. The number on the white background is your baby’s head circumference.
Infant Boy Growth Chart
According to the National Center for Health Statistics, a newborn infant boy’s head circumference usually measures around 13.5 inches, while a baby girl’s is around 13.3 inches.
The percentile lines for girls and boys are always different.
If you have a baby boy, you will want to know the standards of an infant boy growth chart.
Based on the WHO guidelines, these are the standards for infant growth chart boy measurements:
For one-month-old babies, average height is 21.5 inches, average weight is 9.9 lbs and average head circumference is 14.6 inches.
Two-month-old infant boys are around 22.9 inches in height, 12.3 lbs in weight and 15.4 inches in head circumference.
Four-month-old growth chart standards are around 25.2 inches in height, 15.4 lbs for the weight and a head circumference of 16.3 inches.
At six months, infant boys are expected to be around 26.6 inches in height, 17.6 lbs * As infant boys reach their 9th month, the increase continues with 28.3 inches in height, 19.8 lbs in weight and 17.7 inches for head circumference.
By the time an infant boy is one year old, he is expected to be around 29.8 inches in height, 21.2 lbs in weight and a head circumference of 18.1 inches.
Explanation of Infant growth chart boy figures
The figures indicated above are just standards of an infant boy growth chart.
There is no comparison or judgement necessary for a slight deviation from the infant growth chart boy standards.
What matters is that your baby boy shows significant improvement every time you visit the pediatrician. It also does not matter whether your baby is breastfed or formula fed.
Breastfed baby boys usually eat a lot especially in the first few months, but the growth rates do not indicate any large difference.
If your baby boy is formula fed, he should still show signs of growth and a steady increase in development.
Infant Girl Growth Chart
If you have a baby girl, there are some things you need to consider before you start reading her infant growth chart.
There may be times when you or the doctor will realize that your infant growth chart girl measurements were incorrect.
Regardless of gender, when a baby squirms or moves around while on the infant scale, this can cause some mistakes in the results.
The most important thing to consider when examining the infant growth chart girl standards is that your child’s growth rate is good and steady.
The percentage matters much less than continued development when examining the infant growth chart girl standards.
As per the recommendations of the World Health Organization, the ideal height and weight for infant girls ranges from 45.6 to 52.7 cm for height, 2.4 to 4.2 kg for weight and 31.7 to 36.1 cm for head circumference for infants aged 0.
Height ranges from 69.2 to 78.9 cm, weight from 7.1 to 11.3 kg, and head circumference 42.3 to 47.5 cm for infant girls aged 12 months.
If you compare these figures with those of the boys (above), it is obvious why there is a separate growth chart for each gender.
The best way to understand infant growth charts is to schedule a discussion with your baby’s pediatrician.
Medical professionals are the best sources for understanding the value, complications and instructions for monitoring infant boys and girls growth rates.
Infant Growth Chart Reference;
 Centers for Disease Control and Prevention; Clinical Growth Charts, June 16, 2017.