Hi Doctor, My Wife Has A Total Thyroidectomy Right After

Hi Doctor,
My wife has a total thyroidectomy right after we had our son born in 2011. Ever since she has been on Synthroid 100 mcg with very few fluctuations. Last year, she became pregnant once again and miscarried at the end of first trimester (we informed our endocrinologist right after we knew about pregnancy and got dosage increased). A year later she is pregnant now and is most likely in her 9th week. The blood work showed that she has 8.9 TSH and immediately was moved to 150 mcg dosage. This being the first trimester we both are really worried about the developmental problems of the fetus. Could you please give us a little more insight about it.