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
Drug indicated for hypehyroidism during pregnancy: September 2005 
Select and explain. 
A. Prophyltiouracil, B. Carbimazole, C. Iodide, D. Radioactive iodineEnalapril
A: Prophyltiouracil
Answer: A: Prophyltiouracil 
Explanation: 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.