Management of Hyperthyroidism in Pregnancy: Comparison of Recommendations of American Thyroid Association and Endocrine Society

Table 2

Comparison of recommendations of American Thyroid Association and Endocrine Society on the treatment of hyperthyroidism in pregnancy.

Topic	Recommendations
	American Thyroid Association (2011)	Endocrine Society (2012)
Antithyroid (ATD) treatment	PTU is preferred for the treatment of hyperthyroidism in the first trimester, and patients on MMI should be switched to PTU if pregnancy is confirmed in the first trimester. Following the first trimester, consideration should be given to switching to MMI.	Propylthiouracil (PTU), if available, is recommended as the first-line drug for treatment of hyperthyroidism during the first trimester of pregnancy because of the possible association of methimazole (MMI) with specific congenital abnormalities that occur during first trimester organogenesis, and MMI may also be prescribed if PTU is not available or if a patient cannot tolerate or has an adverse response to PTU.; Practitioners should use their clinical judgment in choosing the ATD therapy, including the potential difficulties involved in switching patients from one drug to another. If switching from PTU to MMI, thyroid function should be assessed after 2 weeks and then at 2- to 4-week intervals.
Combination of LT4 and ATD	A combination regimen of T4 and an ATD should not be used in pregnancy, except in the rare situation of fetal hyperthyroidism.	None
Monitoring liver function in women on PTU	None	Although liver toxicity may appear abruptly, it is reasonable to monitor liver function in pregnant women on PTU every 3-4 weeks and to encourage patients to promptly report any new symptoms.
Monitoring of thyroid function	In women being treated with ATDs in pregnancy, FT4 and TSH should be monitored approximately every 2–6 weeks. The primary goal is a serum FT4 at or moderately above the normal reference range.	Same (T)
Surgery	Same (R and T)	Subtotal thyroidectomy may be indicated during pregnancy as therapy for maternal Graves’ disease if (1) a patient has a severe adverse reaction to ATD therapy (2) persistently high doses of ATD are required (over 30 mg/d of MMI or 450 mg/d of PTU) or (3) a patient is nonadherent to ATD therapy and has uncontrolled hyperthyroidism. The optimal timing of surgery is in the second trimester.