"Antithyroid drugs are the main therapy for maternal hyperthyroidism. Both methimazole (MMI) and propylthiouracil (PTU) may be used during pregnancy; however, PTU is preferred in the first trimester and should be replaced by MMI after this trimester. Choanal and esophageal atresia of fetus in MMI-treated and maternal hepatotoxicity in PTU-treated pregnancies are of utmost concern. Maintaining free thyroxine concentration in the upper one-third of each trimester-specific reference interval denotes success of therapy. MMI is the mainstay of the treatment of post partum hyperthyroidism, in particular during lactation."
http://www.ncbi.nlm.nih.gov/pubmed/21389085
IIRC about 30% of women have thyroid enlargement during pregnancy.
The levels can get normal after delivery, and there is a 50% chance thyroid size will get to normal as well.
How about blood flow within the thyroid? any numbers representing the measurements?
Also the doctor said my body was fighting it so she's happy about that I have over active thyroid