Understanding & Using Baby Growth Charts

Learn how to use the World Health Organization’s (WHO) international growth standard statistical distribution growth charts—the Centers for Disease Control and Prevention’s standard charts for ages newborn to 2 years old—to understand the growth of your little one.

You’ve likely seen baby boy and baby girl growth charts during visits to the doctor, but if your physician hasn’t explained them to you, you may find them confusing to read. First, let’s demystify what, exactly, baby growth charts actually measure:

• Baby’s weight compared to age
• Baby’s weight compared to height/length
• Baby’s height/length compared to age
• Baby’s head circumference compared to age (an indicator of brain growth)

By comparing one measurement against another, that will create a data point that falls along a grid onto which several percentiles have been defined. By looking at the line between data points on the baby growth chart, your baby’s rate of development can be tracked against these percentiles.

BMI—a screening tool to figure out weight category—will not be measured until your little one is over 2 years old.

The WHO baby growth charts include baby boy growth charts and baby girl growth charts, and two chart types in each category. To explore each of the World Health Organization (WHO) baby growth charts and print copies for your own at-home use, download them here.

How Will My Baby’s Measurements Be Taken?

The size and growth of your baby will become a routine part of each doctor’s visit. During each baby checkup the doctor will be measuring a few things:

• Head circumference: The doctor or nurse will use a flexible measuring tape just above the eyebrows and ears, around the back of the head. They are measuring the largest circumference of your baby’s head. This measurement is important as it correlates to brain growth.
• Length: Your baby will be measured while they lay flat on a table, head to the soles of their feet. Some doctors use a flexible mat with a moveable headboard and footboard for more accurate results as babies tend to wiggle and move.
• Weight: The doctor or nurse will ask you to undress your baby, removing any clothing for a more accurate reading. Weight will be measured in pounds to the closest ounce.

What Is Percentile Baby Growth & Should It Concern Me?

Baby growth charts are developed using data gained from weighing and measuring thousands of kids to create percentiles. If your little one falls in the 50th percentile, this just means that 50% of those measured at the same age as your baby are higher and 50% are lower. It’s important to note that lower percentiles do not necessarily mean anything is wrong with your baby. There are many factors to consider. For example, if both parents are taller than average or shorter than average it would be normal for the child to follow suit as they grow up.

The rate of growth—not percentile numbers—is what is most important to take away from a baby growth chart. Baby growth charts have been designed to track the trend of your baby’s growth—to ensure baby’s rate of growth is appropriate and follows their percentile’s line.

When Should I Worry About My Baby’s Growth?

Times at which a pediatrician may view baby’s percentile as concerning include:

• When a measurement stays below the 10th percentile for their age or above the 90th
• If the rate of head growth is too fast or slow over time
• If the rate of any measurement’s change doesn’t stay close to one percentile’s range

Baby Growth Timelines: What to Expect

There are other growth benchmarks and age-related milestones to consider while monitoring your growing little one, including feeding-related changes. Here are some common points to keep in mind, based on averages.

Newborn Growth (0 to 3 Months)

• After birth, a newborn may lose about 5 to 10% of their birth weight before leaving the hospital. However, by about two weeks, babies should start to gain weight and grow quickly.
• Typically, when looking at your baby’s growth timeline, your newborn grows faster in the first few months than at any other point in their life.
• If your baby is breastfeeding, it's important they be fed every two to three hours (8 to 12 times per day). If they are bottle feeding, then they may eat every three to four hours in the first few weeks.
• Every month after the first, they should gain about 1.5 to 2 pounds and grow 1 to 1.5 inches. And, a good thing for moms and dads, a newborn may sleep 16 to 17 hours a day the first month of life.

Infant Growth (4 to 8 Months)

• After the 6-month mark, infant growth is not as rapid. However, infants need more calories in relation to their size.
• Every month, your baby should gain about 1.5 to 2 pounds and grow 2 to 3 inches. An infant's weight by 4 to 6 months should be double their birth weight.

Toddler Growth (9 Months and Up)

• By 8 months, the average boy will weigh between 14.5 to 17.5 pounds, while girls will weigh about a half-pound less.
• At 1 year of age, the typical toddler weighs about 3 times their birth weight. However, between ages 1 to 2 a toddler will gain only about 5 pounds.

Your pediatrician will keep track of your baby’s growth, but it’s always good to have a sense of what’s typical and how you can help keep your little one on track by being able to understand baby growth charts. Learn more about your baby’s milestones during their first 2 years.