Weight and Height Percentile
Encyclopedia
Weight and height percentiles are determined by growth charts and body mass index
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...

 charts to compare a child's measurements with those of other children in the same age group. By doing this, doctors can track a child's growth over time and monitor how a child is growing in relation to other children. There are different charts for boys and girls because their growth rates and patterns differ. For both boys and girls there are two sets of charts: one for infants ages 0 to 36 months and another for children ages 2 to 20 years old.

Children with failure to thrive
Failure to thrive
Failure to thrive is a medical term which is used in both pediatric and adult human medicine, as well as veterinary medicine ....

 usually have a weight that is below the 3rd or 5th percentile
Percentile
In statistics, a percentile is the value of a variable below which a certain percent of observations fall. For example, the 20th percentile is the value below which 20 percent of the observations may be found...

for their age and a declining growth velocity (meaning they are not gaining weight as expected) and/or a shift downward in their growth percentiles, crossing two or more percentiles on their growth charts.

Recently it has come to light that current growth charts for infants under 24 months overstate the expected weight of babies and lead to potentially obese children. This is because the original charts produced in 1977 were based on samples of middle class white American babies on high protein bottle fed diets in Ohio. The World Health Organisation has altered these targets in 2006 to represent a more healthy weight.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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