If you have a basic understanding of how to use growth charts, and what the
percentiles mean, and how the breastfed babies differ from the current
standards (higher in the early months, lower in the later months of the
first year), there is no reason not to use the current charts.  If, on the
other hand, you don't understand the purpose of growth charts (to compare
the averages for groups of children) and/or you don't understand what
percentiles mean, like the local pediatrician who thought that a child
growing at the 25th percentile was not growing properly.......

What you need is a little common sense.  Track the child's weight over time,
factor in the parent's and siblings growth patterns and adult size, look at
how the child is doing developmentally, look at the number of wet and dirty
diapers for little ones, look at how content the child is......

Don't rely so much on the weight and the charts.  When I do my presentation
on growth at conferences I talk about what can happen at the doctors office:

First visit: baby is weighed on the front scale at the office, fully
clothed, with a full bladder and bowel and stomach.

Second visit: baby is weighed on the back scale at the office, naked, has
just peed and had a huge blow-out bowel movement and hasn't nursed for 3 hours.

Conclusion:  Baby hasn't gained enough.

Most of the scales at doctors' office (not private LC practices where you
might find a Medela scale) are seldom calibrated, are used to weigh hundreds
of babies a week, and may not be very precise to begin with, if they are a
low quality scale.

Michelle Lampl's work has shown clearly that babies don't grow in a linear
fashion, they grow in fits and starts.  Catch a baby right before a spurt,
and s/he may look like they're not doing well.  Catch a baby right after a
spurt, and the diagnosis is overfeeding.  You have to use common sense.  The
best, most accurate, most appropriate charts in the world will be
meaningless if used improperly.  The current charts are *fine* if you use
them properly and know how to interpret them.

Katherine A. Dettwyler, Ph.D.
Texas A&M University