As a follow up question - After 3 days on 50mcg/daily, my son's heartrate was elevated so the Dr's checked his levels again. His TSH was 12 and his T4 was 2.71 (was originally less than .5). Do these results seem reasonable after 3 days? I was told we would have to wait 4-6 weeks to see any significant change in TSH levels.
you are right, tsh can rise later in premies and need more time to come down, but whew over 300 this is indeed congenital hypothyroidism, and indeed thyroid hormone was indicated, you should be fine with treatment started at that time, the dose sounds appropriate, usually it is about 7.5 to 10 mcg per kg starting dose but with the tsh that high sometimes we go higher, wait for repeat labs, followup with peds endo