I just saw this man, Dr. Steven Hotze, on the Early Show (CBS) this morning. One of the things he was talking about was how women get too much estrogen or progestrone after having a baby and it lowers there thyroid function. He also talked about how your lab tests can be in the normal range but you still have low thyroid. He mentioned using Armour Thyroid instead of Synthyroid. He is located in Texas.
I didn't get the name of his book, but it had something to do with hormones.