REVIEW OF ANTITHYROID DRUG-USE DURING PREGNANCY AND REPORT OF A CASE OF APLASIA CUTIS

Thioamide therapy has improved the outcome of pregnancies complicated by maternal hyperthyroidism, without long-term effects on cognitive an d somatic development. However, there remain questions concerning whet her these drugs, especially methimazole (MMI), may be associated with aplasia cutis congenita (ACC) and how best to avoid impairment of feta l thyroid function during their use. We report an example of ACC and r eview the relevant literature. We conclude that there is insufficient evidence either to establish or eliminate a direct causal relationship between ACC and MMI use. Since propylthiouracil is an equally effecti ve antithyroid agent and has not been associated with ACC, it is the p referred thioamide for hyperthyroidism during pregnancy. Our review al so indicates that impairment of neonatal thyroid function may be minim ized by using a thioamide dose that is just sufficient to maintain the maternal serum free thyroxine concentration in the high normal or sli ghtly thyrotoxic range.