Growth curves: what are percentiles

Growth tables or curves or percentiles are used to compare height, weight, and other dimensions such as head circumference with the average measurements of children of the same age.

Growth curves were obtained from information collected on thousands of children . Thanks to all these data, the measures considered “normal” were established for each age and gender.

By collecting the child’s measurements over time and inserting them in the percentile graphs , curves are obtained which are used by the pediatrician or referring physician to evaluate the child’s growth and check for any health problems.

If the curves obtained have a parallel trend and are included in the percentile range, the child’s growth is normal.

What are growth percentiles?

Growth charts are also called percentile charts.

Percentiles are the lines that define the range of measurements considered normal for that specific age of the child.

For example, if a child’s height is in the 25th percentile, it means that 25 out of 100 children are shorter than him and 75 are taller than him at the same age.

If a child’s height is in the 50th percentile, it means that 50 out of 100 children are taller than him and 50 out of 100 children are shorter than him.

If instead the height is at the 90th percentile it means that 10 out of 100 children are taller than him and 90 out of 100 children are shorter than him.

These are all values ​​that fall within the growth averages.

It is very important to evaluate growth over time and see if this growth follows the trend of the graph lines, not so much if at a certain moment the child is exactly at the 50th percentile.

Growth rate and stature depend on hereditary factors. If a child is smaller than average but is growing normally in line with growth curves, I don’t have to worry.

When are measures of concern?

If the growth curves that we parents or the pediatrician compile have a parallel trend with respect to the lines of the graph, it means that the child is growing regularly and constantly.

The pattern can be a cause for concern when:

• one of the measures remains below the 10th percentile or above the 90th percentile for her age.
• the head grows too slowly or too quickly over time.
• a measurement does not follow the trend of the lines in the graph: for example the pediatrician might be concerned if a child at 6 months was at the 75th percentile, but then at 9 months he moves to the 25th percentile and drops even lower at 12 months.

Check your child’s measurements on the growth charts

You can track your baby’s measurements yourself and compare them to growth percentiles:

Important notices

The growth data must always be evaluated and interpreted by the paediatrician who takes into consideration the weight, height, constitution of the parents, the age and state of health of the child and previous growth values.

Each child has his own times and his own growth pattern: only a doctor can evaluate whether or not growth is within the norm or if a growth disorder is suspected