Dear all: I can't even count the number of maternal and child nutrition and anthropometry courses I have sat through. NEVER until I became a lactation consultant did I hear of the rule of doubling and tripling the weight as a rule of thumb. There are very serious problems with this approach. First, there is the mere statistical problem of regression to the mean. With any measurement we take, whether it is a clinical observation, mechanical measurement, or biochemical value --- there is measurement error. This means that any value can be high or low and for babies who are weighed at birth, some of the very high and very low values are due to measurement error. At the next measurement is it highly unlikely that the measurement error will be in the same direction. So there is a greater chance that the value will be higher if the value was low, or lower if the value was high at the next measurement. This is known as regression to the mean. Second, if there was a problem in utero that caused that baby to grow at higher or lower than the rate that that baby should have grown, it may be corrected in the extrauterine environment. A baby that was growth retarded because of poor placental growth may flourish once it gets breast milk. A baby that had macrosomia because of gestational diabetes may then be able to grow and a slower and healthier rate. So, again this contributes to APPARENT "catch up" and "catch down" growth. Third, birth weight is not predictive of future size --- so the genetic factor (which is MINIMAL on a POPULATION basis --- all ethnicities grow at a very similar rate when they have good nutrition) on an INDIVIDUAL basis can kick in and if the baby is fed according to cues should grow more at the genetically determined rate. Fourth, when a baby slows down in growth --- whatever happened early on when the baby was growing according to a chart may no longer be relevant. It does NOT help the problem solving of whether or not the baby is growing at a healthy rate or not. Really, a doubling or tripling is even more crude than what was LONG AGO discarded in international nutrition circles. We used to use percentages, percentiles and z-scores of average values. That does not work on an individual basis and should NEVER be used for diagnostic purposes. Using some statistical method based on average weight is only marginally useful on a population basis to figure out if a nutrition program had an impact. The pattern of growth is but a clue to investigate further. The far more important factor is how you investigate into both the infant's and maternal behavior and developmental milestones. Every now and again you get a zebra of some hormonal factor such as changes in mom's thyroid level or something rare that was never diagnosed in the infant. I have to say that I was shocked that these type of questions were used on the IBCLE exam. And I would probably still fail those questions because I still think the doubling or tripling time is NOT what we should be evaluating. Best, Susan *********************************************** Archives: http://community.lsoft.com/archives/LACTNET.html To reach list owners: [log in to unmask] Mail all list management commands to: [log in to unmask] COMMANDS: 1. To temporarily stop your subscription write in the body of an email: set lactnet nomail 2. To start it again: set lactnet mail 3. To unsubscribe: unsubscribe lactnet 4. To get a comprehensive list of rules and directions: get lactnet welcome