Hyperthyroidism is more common in women and the sensitivity of thyroid function changes during pregnancy. Excess levels of
thyroid hormones and
thioamides have a major impact on maternal and fetal outcomes. Our aim was to perform an extensive literature review and provide relevant details concerning the analytical and clinical aspects of the potential effects of the two main drugs used (
methimazole and
propylthiouracil) in newborns. A thorough literature review was conducted using PubMed and Google Scholar databases. In total, 10 relevant studies were identified and data from these studies were extracted and then extrapolated into results after analysis. Three out of four studies that used
methimazole and
carbimazole, one and two, respectively, showed adverse fetal outcomes requiring surgical management for congenital anomalies like aplasia cutis, patent vitellointestinal duct, and
gastroschisis. Out of the three studies that used
propylthiouracil, one baby underwent surgery for bilateral
pyelectasis,
vesicovaginal fistula, anal
stenosis, and
polydactyly. The findings of the aforementioned studies provide enough evidence to imply that the use of
methimazole and
carbimazole to treat antenatal
hyperthyroidism has worse fetal outcomes than the use of
propylthiouracil. Also, given the paucity of data in the existing literature regarding
propylthiouracil's effects on newborns, further studies in this demographic are needed.