Antithyroid Drug Treatment in Pregnancy

摘要

The association with MMI/CBZ had also been noted in a retrospective study of the Swedish Medical Birth Regis- ter and the Swedish Register of Congenital Malformations (11). The reports of choanal/esophageal atresia not asso- ciated with MMI exposure were very rare, whereas four cases observed over a 5-yr period were noted to be asso- ciated with MMI in the first trimester. No reports of these malformations were associated with PTU exposure in that study. From this evidence it does appear that we can rea- sonably state that first-trimester exposure to MMI/CBZ is associated with a small but significant risk of congenital abnormalities in the neonate, some of which are very se- vere. As pointed out, prospective cohort studies require a very large sample size to estimate the risk of rare condi- tions such as choanal atresia. Retrospective studies are easier to perform but are more subject to bias due to im- perfect recall (12). So far, no study large enough to defi- nitely prove that PTU is not associated with malforma- tions has been done. Two cases of aplasia cutis have indeed been reported in neonates exposed to PTU (13, 14). It is reasonable to conclude that the risk of PTU-associated abnormalities is very much less than those related to MMI/ CBZ. From the studies cited, there was no relation to the dose of drug and the appearance of a congenital anomaly.