How to Understand Baby Growth Percentages

As your newborn baby grows, it's important for you and your doctor to monitor how she is doing. Growth charts show percentiles that measure how your child rates in terms of height, weight and head circumference, as compared to the average American baby. They can be tricky to understand, but it's important to know what the charts are telling you---so you and your doctor can keep your child healthy.

Things You'll Need

• Cloth tape measure
• Scale
• Computer
• Internet access
• Doctor

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Instructions

• 1

  Measure your baby's weight, length and head circumference.

• 2

  Download a PDF of the growth chart you want to look at for your child. Your doctor will also show you a chart. The charts were released by the National Center for Health Statistics. For infants, newborns to 36 months, there are separate charts for girls and boys. One shows length-for-age and weight for-age and the other shows head circumference-for-age and weight-for-length. They are available on the Centers for Disease Control and Prevention website.

  According to the CDC, there are two sets of charts, the first of which shows the outer limits of the curves at 5th and 95th percentiles; these are most useful for the majority of Americans. Set 2 shows the 3rd and 97th percentiles as the outer limits; these may be useful to assess the growth of babies with special needs.

• 3

  Find your baby's percentile rating. If you're looking at the chart of height and weight (see the References section), find your child's age on the horizontal grid. Find the baby's weight according to the bottom graph. Follow the curve to approximate your baby's percentile. Do the same for the upper graph that measures length.

• 4

  Understand what the percentiles mean for your child. Your young daughter may lie in the 50th percentile for weight and the 75th percentile for height, for example. That means 50 percent of girls her exact age weigh equal to or less than she does. For height, it means 75 percent of girls her age are the same length or shorter, and 25 percent are taller than her.

• 5

  With help from your doctor, look at the overall growth of your baby. Don't worry so much about how big or small your baby is necessarily, but how he grows. According to BabyCenter, babies often go through growth spurts, in which they will gain weight and length quickly. Your doctor should monitor not just individual spurts, but growth patterns over time.

• 6

  Be concerned if your baby's growth percentages change by a lot. Your doctor will try to figure out if there is a problem or medical reason if your baby all of a sudden drops weight percentile significantly. It's important to note if the child's head is smaller than average size to make sure the brain is developing. And, if your baby is in a highest percentile for weight, watch his growth. You want to may need to decrease feedings if there is a risk of obesity.