I'm not sure if I posted this thought to someone privately, or if I also put it over L'net.  If this is a repeat, I apologize.

I think we are in error if  we say 10% is "normal."  What is usual, and maybe even normal, is for babies to lose SOME weight, for up to three days.  After all, if they're just pooping lots, and taking in little, that will affect their weight.

 But my understanding is that "10% at 72 hours"  is the maximum acceptable weight loss before intervention should be started (unless you have some way of knowing at this time that baby has reached his maximum weight loss, and will start going up from here -- like a trained person sees the baby is actually breastfeeding well, frequently, and long enough, and the full volume of mom's milk is starting to make itself known).

My hospital has now started to rethink even this, with earlier intervention:   8-1/2% before 48 hours is grounds for intervention, at least by pumping and supplementing with the EBM, and by close follow-up at home, if baby is even discharged at that point, both for weight checks, bili assessment, and to make sure the baby is continuing to nurse properly.  (If he isn't nursing well -- A (of LATCH) = 2, we don't usually let him go home.)  Hopefully the PNP who does the follow-up visit gets to watch a feeding, as opposed to getting just mom's subjective report, to make sure the baby is continuing to nurse well, and not just giving the appearance of it.   

The earlier intervention is necessitated by the fact that most of our vag deliveries go home between 24 - 36 hours, and even our C/S couplets go home by 72 hours (barring infection or other complications), and we were having too many readmits for excessive weight loss/dehydration.

Chanita, San Francisco