How do we know if our baby has CH or transient Hypothyroidism?

My nephew is 11 months old. Several weeks ago my sister-in-law took him to the pediatrician because she felt that something was "off." Her main concern was that my nephew was not eating as well and is also very small for his age. She felt that being with him everyday, she noticed that after 6 months he hadn't grown as much as he should. To my knowledge, he had no other symptoms. He is an alert and happy baby. He has since been tested and is taking synthroid for hypothyroidism. Incidentally, he had low iron levels as well. My sister in law is awaiting an appt with a specialist. Is it common practice to do heel sticks on new borns to test T4 and TSH levels? I'm concerned that this is congenital and was overlooked. I read that ideally newborns with CH should be immediately placed on meds. (our baby was nearly 10 months!). Does this mean that he has transiet hypothyroidism? What should our concerns be about his growth and development patterns now, going forward?
Best,
Melissa RN

[Mark Lupo, M.D.]

I have little to no experience with neonatal thyroid disease, but you are right - babies are screened for thyroid dysfunction - I am sure you could get documentation of this if needed for your nephew.  Sounds like seeing a specialist is the right thing.  Keeping thyroid normal is critical to growth and development - now that he is on synthroid, it should be monitored on a regular basis.