Aplasia Cutis Congenita and Dysmorphic Syndrome After Antithyroid Therapy During Pregnancy

Aplasia cutis congenita (ACC) is alleged to be a side effect of antithyroid therapy during pregnancy. This occurrence is uncommon. Only 24 cases have been reported in the literature. In France, there has been no report by the National Center of Pharmacovigilance since 1985. We report a 39-year-old woman with no significant past history in whom Graves disease developed without eye symptoms. She was using methimazole 60 mg daily for 3 months, followed-up by propylthiouracil until delivery. At birth, the newborn had a scalp defect on the vertex, measuring 7- × 2-cm, transient hypothyroidism, and a dysmorphic syndrome (flat face, low-set ears, upper lip retraction, xiphoid funnel, finger-like claws, and low-set fifth finger). At age 1 year, the aplasia cutis was treated surgically. Aplasia cutis is a rare disorder, sometimes associated with other malformations. The mothers with hyperthyroidism who delivered children with reported cases of ACC have used either carbimazole or its active metabolite, methimazole, during early pregnancy. The relationship between methimazole or carbimazole therapy during pregnancy and ACC in the newborn remains to be proven. Nevertheless, to the authors’ knowledge, no case has occurred in which the mother has used only propylthiouracil. Therefore, consideration should be given to the exclusive use of propylthiouracil in pregnancy.