Weight and height percentiles are determined by
growth chart
A growth chart is used by pediatricians and other health care providers to follow a child's growth over time. Growth charts have been constructed by observing the growth of large numbers of healthy children over time. The height, weight, and hea ...
s and
body mass index
Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...
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 ages 2 and above.
Children with
failure to thrive
Failure to thrive (FTT), also known as weight faltering or faltering growth, indicates insufficient weight gain or absence of appropriate physical growth in children. FTT is usually defined in terms of weight, and can be evaluated either by a low ...
usually have a weight that is below the 3rd or 5th
percentile
In statistics, a ''k''-th percentile (percentile score or centile) is a score ''below which'' a given percentage ''k'' of scores in its frequency distribution falls (exclusive definition) or a score ''at or below which'' a given percentage falls ...
for their age and a declining growth velocity (meaning they are not gaining weight as expected).
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 Organization has altered these targets in 2006 to represent a more healthy weight.
References
{{reflist
External links
Body Mass Index Percentile Calculator Tool for Infants
Medical signs