How do the WHO standards for child growth work

Growth & stunted growth


Growth and weight development from birth to the age of 4

Parents are happy about their child's prosperity, every centimeter, every gram is "a success", calms and makes you feel confident. This is particularly true of infancy at a time when there are still few other parameters that provide information about whether "everything is going right", whether "everything is being done right". During this development phase, pediatricians also pay a lot of attention to thriving, i.e. increasing body weight and length. Insufficient weight gain, and often followed by delayed growth in height, can indicate an inadequate absorption of important nutrients (medical term: malabsorption) in the first year of life.

Fortunately, such diseases are very rare in infancy!

Growth.at provides suitable comparative values ​​for healthy children for assessing how well they thrive in infancy and toddlerhood:

The so-called "WHO standards" made available by the World Health Organization (WHO).

The term “standard” means that under optimal conditions with regard to nutrition, social and environmental factors, a course of the length and weight / BMI values ​​in the statistical “normal range” is expected.

The pediatrician will initiate a medical assessment if there is a drop in the respective percentiles or SDS.

References of body size and nutritional status beyond infancy and toddler age

From the age of 2-5, other factors increasingly take control of growth: genes and hormones.

For this reason, from late childhood onwards, comparative values ​​are used that are geographically, genetically or ethnically representative.

The first Austrian reference data are available for wwachs.at (APEDÖ references for body height and body proportions).

The percentile at which a child grows is mainly determined by genes. The "expected size" of a child can be represented with a very simple formula as the so-called "genetic target length (ZL) 55". For orientation about the "genetic background", growth.at shows the ZL both as an SD score (see master data) and in the percentile curve for body size. The "genetic target length" is additional information, not a prognosis and also not an expression of personal expectations!

Does my child have a stunted growth?

The percentile line on which a child grows depends above all on the "genetic background", that is, on the height of the parents. However, it is by no means uncommon for children to grow on lines deviating from the target genetic length percentile.

A body size at the statistical marginal areas or below or above is not synonymous with a growth disorder!

Typical for familial-genetic norm variants is growth on a line, between two lines or also growth in parallel below the 3rd or above the 97th percentile.

If the growth of a child is very different from the genetic background and / or percentiles are "crossed", the pediatrician may initiate further examinations.

An over- or under-production of hormones always leads to a "crossing" of the percentiles after the 2nd to 3rd year of life. Here the actual growth is reduced or accelerated, one speaks of a growth disorder.

If there is a growth disorder, it is important to assess the so-called body proportions (seat height, leg length). For this, the ratio of seat height and leg length is calculated. Reference values ​​are available from the age of 4.

Special references

Specific references are available for some defined growth disorders. Growth.at offers reference curves for girls with Turner syndrome, children with Noonan syndrome and children with achondroplasia. An expansion of the offer is being planned.

Is my child overweight or underweight?

The so-called Body Mass Index (BMI) is used to assess the nutritional status (BMI = body weight in kg by body surface area in m2). The BMI formula already takes into account the influence of body size on body weight. There are good limits for adults to differentiate normal weight (BMI 18-25) from underweight (BMI <18) and overweight (BMI> 25).

The situation is more complex for children: Since the nutritional status of children, measured by the BMI, changes from infancy to adulthood, the absolute BMI values ​​are not used analogous to the growth in length (those in the table of measurements according to the weight from the above formula are calculated), but in turn special scores are calculated:

The WHO provides very suitable comparative values ​​for the nutritional status of healthy infants and young children through the WHO standards from 0-4 years. Growth.at calculates the SD-Score according to these standards, the result is shown in the table.

In analogy to the SDS for body size, a value of "0" means an average nutritional status (weight in relation to body size), with SDS> +1 one speaks of overweight, with> +2 of obesity. Underweight becomes less clear on an SDS < -2,0="" definiert.="">

In infancy, the ratio of "body weight to body length" is also informative. Growth.at shows this value in its own percentile curve.

To assess the nutritional status after the age of 5 years, the WHO uses very old data sets. These come from a time when children were not as often overweight as they are today. Since some health institutions still use this WHO BMI-SDS to initiate measures if necessary, growth.at also makes this score available in the table of measured values.

In rare cases only weight data is available, but not length data, so that it is not possible to calculate the BMI. For this reason, Growth.at also provides weight data between the ages of 0 and 5 years as an SDS based on WHO standards.

Recommendation: Growth.at, the APEDÖ and ÖGKJ recommend the use of the so-called Equi-BMI: Here, the current data on the nutritional status of Austrian children are statistically calculated in such a way that an interpretation of risk factors for later cardiovascular diseases is included. The Equi-BMI values ​​are shown both in the table of measured values ​​and as a separate graphic, with the classes "normal", "overweight" and "underweight" being drawn directly on the curve.

What is the "bone age"?

In childhood, the so-called growth plates, i.e. the tissue in which the bones grow in length, are visible in the X-ray image. The skeletal maturity of a child (often called "bone age") is defined by comparing numerous sections in the hand skeleton (on the so-called "carpal x-ray") with age-typical comparison images. A specialist in stunted growth should determine whether performing a carpal x-ray on your child provides an important additional finding.