title: Pharmacologic treatment of hyperthyroidism during pregnancy.
abstract: Clinical hyperthyroidism has been associated with an increased risk of maternal, fetal, and neonatal complications. The available antithyroid drugs are methimazole/carbimazole and propylthiouracil. Several case reports and some epidemiologic studies suggest that methimazole/carbimazole exposure during the first trimester of pregnancy is associated with an increased risk of congenital malformations, including ectodermal anomalies, choanal atresia, esophageal atresia, and omphalocele. However, the absolute risk appears to be very small, and it remains unclear whether the association is driven by the maternal disease, the medication, or the combination of both factors. Propylthiouracil exposure has not been associated with an increased risk of congenital malformations and is the recommended drug during the first trimester of pregnancy. Since propylthiouracil-induced hepatotoxicity has been reported in approximately 0.1% of exposed adults and the number of case-reports of severe liver injury is increasing, treatment with low dose methimazole during the second and third trimesters should be considered. Until now, there has been no evidence that children prenatally exposed to methimazole/carbimazole or propylthiouracil have an increased risk of neurodevelopmental delay.
authors.affiliation: Teratology Information Service, Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy. matteo.cassina@unipd.it
authors.forename: Matteo
authors.initials: M
authors.lastname: Cassina
authors.forename: Marta
authors.initials: M
authors.lastname: Donà
authors.forename: Elena
authors.initials: E
authors.lastname: Di Gianantonio
authors.forename: Maurizio
authors.initials: M
authors.lastname: Clementi
mesh_terms: D013956:Antithyroid Agents / Q000008:administration & dosage / Q000009:adverse effects*; D002231:Carbimazole / Q000008:administration & dosage / Q000009:adverse effects*; D002754:Choanal Atresia / Q000139:chemically induced / Q000517:prevention & control; D004334:Drug Administration Schedule; D004933:Esophageal Atresia / Q000139:chemically induced / Q000517:prevention & control; D005260:Female; D006554:Hernia, Umbilical / Q000139:chemically induced / Q000517:prevention & control; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy*; D007231:Infant, Newborn; D018811:Maternal Exposure; D008713:Methimazole / Q000008:administration & dosage / Q000009:adverse effects*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000187:drug effects; D011441:Propylthiouracil / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D013956:Antithyroid Agents; D008713:Methimazole; D011441:Propylthiouracil; D002231:Carbimazole