ATA Guidelines Tools

23 Pregnancy 88. The diagnosis of hyperthyroidism in pregnancy should be made using serum TSH values, and either total T 4 and T 3 with total T 4 and T 3 reference ranges increasing to 1.5 times above the nonpregnant range by the 2nd and 3rd trimester or free T 4 and total T 3 estimations with trimester-specific normal reference ranges. (S-L) 89. Transient hCG-mediated TSH suppression in early pregnancy should not be treated with antithyroid drug therapy. (S-L) 90. ATD therapy should be used for overt hyperthyroidism due to GD during pregnancy. • PTU should be used when ATD therapy is given during the first trimester. • MMI should be used when ATD therapy is started after the first trimester. (S-L) 91. In women who develop hyperthyroidism during their reproductive age range, the possibility and timing of future pregnancy should be discussed. Because of the risks of the hyperthyroid state on pregnancy and fetal outcome, the ATA suggests that women should postpone pregnancy until they have become euthyroid with therapy. (S-L) 92. The ATA suggests that women with hyperthyroidism caused by GD that require high doses of ATDs to achieve euthyroidism should be considered for definitive therapy before they become pregnant. (W-L) 93. Women with hyperthyroidism caused by GD who are well controlled on MMI and desire pregnancy have several options: • Patients could consider definitive therapy before they become pregnant. • Patients could switch to PTU before trying to conceive. • Patients could switch to PTU as soon as pregnancy is diagnosed. • Appropriately selected patients could withdraw from ATD therapy as soon as pregnancy is diagnosed. If ATD therapy is withdrawn, thyroid function should be assessed weekly throughout the first trimester, then monthly. (W-L) 94. The ATA suggests that women who are treated with ATD and who may potentially become pregnant should be instructed to perform a pregnancy test within the first days after a missed or unusually light menstrual period. (W-L) 95. The ATA suggests that a woman who tests positive for pregnancy according to Rec. 94 contact the physician responsible for the ATD therapy the same day to discuss future treatment options. (W-L)

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