Management of thyroid disease during pregnancy presents unique challenges due to physiologic changes that occur. These include
• Serum levels of thyroxine-binding globulin (TBG) increase along with estrogen; in turn, total thyroxine (T4) and triiodothyronine (T3) levels increase.
• Human chorionic gonadotropin (hCG) stimulates the thyroid stimulating hormone (TSH) receptors.1
Since hCG and TSH share similar glycoprotein subunits, a transient suppression of TSH—especially around weeks 10 to 12, when hCG concentrations peak—is considered a physiologic finding. Interpretation of thyroid function testing should be made in relation to the hCG-mediated decrease in serum TSH levels.2
The following four cases will help guide your clinical management of thyroid disease in both preconception and pregnancy. Inadequately controlled thyroid dysfunction can lead to poor pregnancy outcomes for both mother and child, which will be further discussed.
Continue for Case 1: Stable Hypothyroidism >>