I was trying to wrap my brain around this some time ago as to why the levels are higher.  Besides the fact that babies grow at a rapid rate in the last weeks of pregnancy and the first year or so of life and that 17 OHP being higher helps with that rapid growth spurt...I was also thinking that maybe the adrenal glands are not fully matured---especially so in preemies when they are probably not mature enough to cope.  Therefore not making cortisol very well and thus the fact that they make lot’s of 17 OHP in abundance as well as other hormones.  

I think really they should do a genetic test though within a week of the supposed diagnosis to actually confirm that it IS CAH that is causing this basically.  I know they have newborn screening now and in some cases it is patently obvious that they have CAH because the 17 OHP levels would be through the roof, but in cases like this where there is doubt, when they start treatment that can affect a babies growth and development they really ought to confirm the diagnosis by means of genetic tests also about a week after the birth at whatever gestation it is.  My son had genetic tests done within a few days of us being given a diagnosis and although it took a full week to come back and tell us the sex was correct and that the diagnosis was correct also, had it not been CAH, he would have been pulled of steroids when they received those back.  This is really how it should be basically for ALL babies that have a diagnosis.  

I don’t know if you had ALL heel pricks for the three tests or full blood draws and the genetic tests would have to be full blood draw I would imagine.  As much as this is uncomfortable for babies, I think it takes priority when they have started treatment and a babies growth can be affected if they get it wrong.  There is every possibility that your baby could have mild CAH, but no matter what the strain or severity, these things should always have to be confirmed with genetic tests as it is no fun for parents who sit wondering if they are dosing stuff they simply don’t need to.  once a genetic confirmation is received you can quit wondering and get down to accepting the diagnosis or in thanking your lucky stars they don’t have it.  One or the other.  My two cents worth...