Antithyroid drugs in pregnancy

The answer is c. (Hardman, p MOL) Propylthiouracil is more strongly protein bound and crosses the placenta to a lesser degree than methimazole and is, therefore, the safest antithyroid drug in pregnancy... 

Mandel SJ, Cooper DS. The use of antithyroid drugs in pregnancy and lactation. J Clin Endocrinol Metab 2001 86(6) 2354-9. 

Bowman P, Osborne NJ, Sturley R, Vaidya B. Carbimazole embryopathy implications for the choice of antithyroid drugs in pregnancy. QJM 2012 105(2) 189-93. 

Yoshihara A, Noh J, Yamaguchi T, Ohye H, Sato S, Sekiya K, et al. Treatment of Graves disease with antithyroid drugs in the first trimester of pregnancy and the prevalence of congenital malformation. J Clin Endocrinol Metab 2012 97 2396-403. 

Neonatal hypothyroidism has been reported after maternal use of antithyroid drugs (106,107). Transient neonatal hyperthyroidism in a female child born to a mother who had been treated with potassium iodide and carbimazole during pregnancy was followed by sexual precocity (108). 

The 24-hour RAIU wiU be suppressed to less than 2% during the thyrotoxic phase of painless thyroiditis. Antithyroglobuhn and antimicrosomal antibody levels are elevated in more than 50% of patients. Painless thyroiditis frequently occurs during the immediate postpartum period, and individual patients may experience recurrence of the disease with subsequent pregnancies. Patients with mild hyperthyroidism and painless thyroiditis should be reassured that they have a self-hmited disease. Adrenergic symptoms may be ameliorated with propranolol. Antithyroid drugs are not indicated because they do not decrease the release of preformed thyroid hormone. 

Antithyroid drugs Noninvasive Lower initial cost Low risk of permanent hypothyroidism Possible remissions due to immune effects Low cure rate (30%-80% average 40%-50%) Adverse drug reactions Drug compliance Lirst-line treatment in children, adolescents, and in pregnancy Initial treatment in severe cases or preoperative preparation... 

Thyrotoxicosis occurs in about 0.2% of pregnancies and is caused most frequently by Graves disease. Antithyroid drugs are the treatment of choice radioactive iodine is clearly contraindicated. Historically, propylthiouracil has been preferred over methimazole because transplacental passage was thought to be lower however, both propylthiouracil and methimazole cross the placenta equally. Current data suggest that either may be used safely in the... 

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