Understanding baby growth charts

An infant growth chart helps you, your doctor and other health professionals keep track of your baby's growth.

Growth charts record changes in your baby's measurements, including their:

• length (height)
• weight
• head circumference

These measurements are recorded on the chart so you can see how they change over time. The measurement is recorded on the vertical (up-and-down) axis, and your baby's age is recorded on the horizontal (side-to-side) axis.

Your baby's growth is a good indicator of their overall health and nutrition. TGrowth charts are used to compare your baby's growth with that of other babies of the same age. Different charts are used for:

• males and females
• infants and older children

Infant growth (aged 0 to 2 years) is calculated using the World Health Organization's (WHO) growth standards. From 2 years of age, most states and territories use growth charts based on those from the US Center for Disease Control (CDC).

You will find a growth chart in your child's personal health record. Depending on where you live, this record is known by different names. The book might be blue or red, or another colour, depending on which state or territory you are in.

You can also register your baby for My Health Record. This is a digital health record that healthcare providers can upload health information, including information about your baby's growth.

The percentile chart is the most common type of growth chart and shows growth by using 'percentiles'. Below are some examples:

• A baby on the 50^th percentile for weight is right in the middle of the normal weight range: half of babies their age are lighter, and half are heavier.
• A baby on the 5^th percentile for weight weighs less than 95% of other babies of that age. Put another way, if 100 babies of the same age were lined up from lightest to heaviest, a baby on the 5th percentile would be one of the 5 lightest babies.
• A baby on the 90^th percentile for weight weights more than 90% of other babies that age. Put another way, if 100 babies of the same age were lined up from lightest to heaviest, a baby on the 90th percentile would be one of the 10 heaviest babies.

Like adults, babies come in all shapes and sizes. Some babies will always be small. Others will always be large. All babies grow at different rates, and 'normal' growth varies a lot. The important thing is that your baby continues to grow at a similar rate.

Growth charts help you track how your baby is growing by showing normal growth curves (i.e., always increasing). You can plot your baby's growth to see if it follows a similar pattern to other babies on that percentile. Remember, your child should not be expected to follow a curve exactly.

Your baby is weighed and measured at birth. It's normal for babies to lose some weight right after birth, so it's usual for your baby to be weight again at 2 weeks old to see whether they have returned to their birth weight. After that, it may be helpful to track their growth monthly. Your baby should grow steadily over their first year and throughout childhood.

Growth charts are used until your child turns 18.

There are recommended routine health checks for your baby; the exact timing and frequency depends on which state or territory you live in. You can talk to your child health nurse or doctor about when to have these health checks, to make sure your child is growing and developing normally.

Special infant scales are used to weigh babies who weigh up to 20kg. Newborns and young babies are placed on these scales lying down, without any clothes and with their nappy removed, to ensure the measurement is as accurate as possible.

After 2 years of age, your child can be measured standing up in light clothes.

Your baby's head circumference should be measured using a tape measure.

If your child was born prematurely, a 'corrected' age is used to measure their growth. This means adjusting their age by the number of weeks they were born early. This corrected age is recorded on all their growth charts until they turn 2 years old. For example, a 4 month old baby born 1 month early would have a 'corrected' age of 3 months. Their growth measurements at 4 months old would be plotted at the '3 month' age line of their growth chart.

Measuring your baby's growth can help confirm that they are healthy and developing as expected. However, it's not the only way to tell if they're healthy.

Other signs that your baby is healthy and feeding adequately include:

• having at least 5 very wet nappies each day
• having pale urine (wee)
• making well-sized, soft poos
• reaching their birth weight by the time they are 14 days old
• being generally content between feeds

All babies lose some weight in the week after birth. They usually regain this weight by 2 weeks of age. Most babies double their birth weight by 4 months of age.

Weight gain can be affected by feeding difficulties, infections or other medical problems. If you are ever worried, talk to your doctor or child and family health nurse.

If your baby's growth percentile drops at a faster rate than expected or your baby continues to have low weight gain — talk to your child and family health nurse or doctor. They will assess the child's growth trend to see if there is any reason to be worried.

Remember, don't compare your baby's growth to that of another baby's. The important thing is that they continue growing steadily in their first year and throughout childhood.