This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'Drug of choice for hyperthyroidism in pregnant female: \nSelect and explain. \nA. Propylthiouracil, B. Carbimazole, C. Sodium iodide, D. Radioactive iodine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. PropylthiouracilDrug of choice for hyperthyroidism in pregnancy is propylthiouracil (first trimester) whereas the in second and third trimester carbimazole is used. They inhibit the conversion of T4 to T3 which is active form of thyroid hormone.', 'role': 'assistant'}]