Endocrine Abstracts

In euthyroid women normal pregnancy is associated with a rise in free thyroxine and fall in TSH levels attributable to high levels of hCG in the first trimester. In hypothyroid women free thyroxine tends to fall and TSH rises if the dose of thyroxine is not raised, due to further pregnancy - associated changes including a rapid rise in thyroxine-binding globulin and increased renal clearance and placental metabolism of thyroid hormone. Fetal thyroid development occurs by 12 we...