Endocrine Abstracts

Thyroid disorders are common among women of childbearing years. However, the diagnosis of thyroid disorders during pregnancy is confounded by the normal alteration in thyroid physiology. Serum TSH levels decrease at the end of the first trimester, mirroring the increase in serum hCG levels; hCG is thyrotropic and causes a slight increase in serum free T4 concentrations. With the drop in serum hCG as pregnancy progresses, serum free T4 levels decline and may decrease below the ...