This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Drug indicated for hypehyroidism during pregnancy: September 2005 \nSelect and explain. \nA. Prophyltiouracil, B. Carbimazole, C. Iodide, D. Radioactive iodineEnalapril', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Prophyltiouracil The key antithyroid drugs - also known as thionamides -include propylthiouracil (PTU), methimazole (MMI) and carbimazole. Though effective in pregnant women, babies of mothers taking antithyroid drugs have a high risk of goiter, hypothyroidism or even cretinism. However, low doses of propylthiouracil is preferred in pregnancy: its greater protein binding allows less transfer to the fetus. For the same reason it is to be preferred in the nursing mother.', 'role': 'assistant'}]