So much so that unless your child is unusually skinny, these won't fit.  My daughter is 7 weeks old and just weighs in at 10 lbs even and 23 inches.  She is skinny and is average length.  She is comfortably fitting into  size 0-3 months (she was in newborn for a while), and meanwhile, the 3-6 months on these is snug around her.

I like this brand and really do love their gowns.  Their footies - the sizing is really off.  These are for parents who would otherwise be complaining "All baby clothing is too bulky around the belly on my baby!"  If you've got this problem, then these are for you.  Otherwise, if you still want to buy these, order up.