Last paragraph very useful!

 

> 

> Well before my doctoral dissertation studies percent weight change was used in

> developing areas of the world to determine which families were eligible for

> nutritional supplements for their infants and young children and/or eligible for

> nutritional counseling.  Percent weight loss was abandoned because it does not

> nearly as reliable as tracking growth along a percentile (or z-score curve).  The

> reason why this is so is because as infants and young children get older, their

> original weight increases so that a particular percent of weight loss may not

> coincide with the percentiles of normal growth.  I remember calculating

> sensitivity and specificity and positive and negative predictive values comparing

> cutoffs using percent weight loss and percentile curves and they do not match.

> This was back in the late 1980s.

> 

> So, for older babies, percent of weight change is NOT an indicator that should

> be used.  The WHO growth charts SHOULD be used and there are criteria on

> their website for how to interpret drops in percentILES.

> 

> The only use I know for knowing percent weight loss is that first check in the first

> week of life that can never really be used without ALSO considering other

> indicators as well.  The simplest way to calculate percent weight loss in

> backward countries like the United States that use pounds and ounces (which

> causes enough math errors to hit in my top 10 list of reasons why

> supplementation is unnecessarily used and cases of failure to thrive are missed)

> is to simply switch the scale from pounds and ounces to grams.  All good scales

> have that switch.  Most babies are weighed in grams at birth.  Simply subtract

> the current weight in grams from the birth weight in grams.  Move the decimal

> point one digit to the left for the birth weight.  You can quickly see if the weight

> loss is greater than 10% in grams.

> 

> Susan E Burger, MHS, PhD, IBCLC, RLC

> 


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