Antithyroid drug use during pregnancy and the risk of birth defects in offspring: systematic review and meta‐analysis of observational studies with methodological considerations
Review of 8 studies (6 ,212 ,322 pregnancies) found an increased rate of birth defects from propythiouracil and methimazole/carbimazole use during pregnancy vs non-exposure (RR 1.16, 95%CI 1.08-1.25, and 1.28, 1.06-1.54 respectively).
Source:
British Journal of Clinical Pharmacology
SPS commentary:
The excess risk of any and major birth defects per 1000 births, respectively, was: 10.2 and 1.3 for prophythiouracil and 17.8 and 2.3 for methimazole/carbimazole. Authors highlight that although still elevated, the risk of birth defects is smallest with prophythiouracil compared to methimazole/carbimazole and may be similar to that of untreated hyperthyroidism.